Magneto-resistance effect element, and method for manufacturing the same

ABSTRACT

A magneto-resistance effect element, including:
         a fixed magnetization layer of which a magnetization is substantially fixed in one direction; a free magnetization layer of which a magnetization is rotated in accordance with an external magnetic field and which is formed opposite to the fixed magnetization layer; a spacer layer including a current confining layer with an insulating layer and a conductor to pass a current through the insulating layer in a thickness direction thereof and which is located between the fixed magnetization layer and the free magnetization layer; a thin film layer which is located in a side opposite to the spacer layer relative to the free magnetization layer; and a functional layer containing at least one element selected from the group consisting of Si, Mg, B, Al which is formed in or on at least one of the fixed magnetization layer, the free magnetization layer and the thin film layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/073,895, filed Mar. 11, 2008, and is based upon and claims thebenefit of priority from the prior Japanese Patent Application No.2007-094474, filed on Mar. 30, 2007; the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magneto-resistance effect elementwhich is configured such that a current is flowed in the directionperpendicular to the film surface thereof to detect the magnetization ofthe element and the magneto-resistance effect element and to a methodfor manufacturing the same.

2. Description of the Related Art

Recently, the miniaturization and the high density recording of a harddisk drive (HDD) is remarkably required and being progressed. In thefuture, it is promised to much develop the high density recording of theHDD. The HDD of high density recording can be realized by narrowing therecording track width. However, the amplitude of the magnetizationrelating to the recording, that is, the recording signal may be loweredas the track width is narrowed, so that it is required that thereproducing sensitivity of the MR head for reproducing the medium signalis enhanced.

Recently, a GMR (Giant Magneto-Resistance effect) head with a highsensitive spin valve film using the GMR film is employed. The “spinvalve” film has such a structure as sandwiching a non-magnetic metalspacer layer between two ferromagnetic layers. The stacking layercomponent structure exhibiting the change in resistance may be called asa “spin dependent scattering unit”. The magnetization of oneferromagnetic layer (often called as a “pinning layer” or “fixedmagnetization layer) is fixed by the magnetization of ananti-ferromagnetic layer and the magnetization of the otherferromagnetic layer (often called as a “free layer” or “freemagnetization layer”) is rotated in accordance with an external magneticfield. With the spin valve film, the intended large magneto-resistanceeffect can be obtained when the relative angle between the pinning layerand the free layer is changed.

A conventional spin valve film is formed as a CIP (Current In Plane)-GMRelement, a CPP (Current Perpendicular to Plane)-GMR element and a TMR(Tunneling Magneto-Resistance) element. With the CIP-GMR element, asense current is flowed along the film surface of the spin valve film.With the CPP-GMR element or the TMR element, a sense current is flowedin the direction perpendicular to the film surface thereof.

With the element which is utilized by flowing the sense current in thedirection perpendicular to the film surface, the spacer layer is made ofan insulating layer in the TMR element and of a metallic layer in theCPP-GMR element.

Herein, a metal CPP-GMR element of which the spin valve film is made ofa metallic layer has a smaller change in resistance to render thedetection of small magnetic field difficult. In this point of view, inReferences 1 and 2, such an attempt is made as inserting a layer made ofat least one selected from the group consisting of Cr, V, Ta, Nb, Sc,Ti, Mn, Cu, Zn, Ga, Ge, Zr, Hf, Y, Tc, Re, Ru, Rh, Ir, Pd, Pt, Ag, Au,B, Al, In, C, Si, Sn, Ca, Sr, Ba, O, N and F in the fixed magnetizationlayer of the free magnetization layer composing the spin dependentscattering unit, thereby enhancing the variation ratio in resistance ofthe CPP-GMR element and thus, thereby enhancing the magneto-resistanceeffect of the CPP-GMR element.

On the other hand, a CPP element with an oxide layer containing currentconfining paths in the thickness direction thereof, which is called asan “NOL (nano-oxide layer)”, is proposed (refer to Reference 3). Withthe CPP element, both of the element resistance and the MR ratio can beincreased due to the current confined path (CCP) effect. Hereinafter,the element is called as a “CCP-CPP element”.

-   [Reference No. 1] JP-A 2003-133614 (KOKAI)-   [Reference No. 2] JP-A 2003-60263A (KOKAI)-   [Reference No. 3] JP-A 2002-208744 (KOKAI)

In the CCP-CPP element, it is required to much enhance the sensitivityof the CCP-CPP element. The sensitivity can be defined as the MR ratio.

BRIEF SUMMARY OF THE INVENTION

An aspect of the present invention relates to a magneto-resistanceeffect element, comprising: a fixed magnetization layer of which amagnetization is substantially fixed in one direction; a freemagnetization layer of which a magnetization is rotated in accordancewith an external magnetic field and which is formed opposite to thefixed magnetization layer; a spacer layer including a current confininglayer with an insulating layer and a conductor to pass a current throughthe insulating layer in a thickness direction thereof and which islocated between the fixed magnetization layer and the free magnetizationlayer; a thin film layer which is located in a side opposite to thespacer layer relative to the free magnetization layer; and a functionallayer containing at least one element selected from the group consistingof Si, Mg, B, Al which is formed in or on at least one of the fixedmagnetization layer, the free magnetization layer and the thin filmlayer.

In the aspect, with a bottom type spin valve film, the functional layercontaining at least one element selected from the group consisting ofSi, Mg, B, Al is formed at at least one of the fixed magnetizationlayer, the free magnetization layer and the cap layer, and with a toptype spin valve film, the functional layer is formed at at least one ofthe fixed magnetization layer, the free magnetization layer and theunderlayer. The functional layer, as described later, may capture theexcess oxygen remaining in spin dependent scattering unit and preventthe diffusion of the excess oxygen so as to prevent the deterioration ofthe spin dependent scattering due to the interface and inside of thefree magnetization layer. Then, since the functional layer contains anelement with smaller atomic number such as Si, Mg, B, Al, the spinpolarization of each conduction electron is not diminished in thefunctional layer.

Also, the functional layer may prevent the diffusion of Mn and the likecontained in the fixed magnetization layer and the diffusion of Ni andthe like contained in the free magnetization layer, leading to theprevention of the deterioration of the spin dependent interfacescattering due to the Ni and the like. Particularly, if the freemagnetization layer exhibits bcc-structure, the structure of the freemagnetization layer can be stable due to the functional layer.Accordingly, the MR ratio of the magneto-resistance effect element, thatis, the CCP-CPP element can be enhanced by the synergy effect of threefunctions as described above.

The three functions are originated purely from the consideration of theinventors so as not to affect the present invention. The presentinvention is characterized in that the MR is enhanced by the functionallayer satisfying the above-described requirements.

In an embodiment of the present invention, the spacer layer includes ametallic layer, e.g., containing at least one element selected from thegroup consisting of Cu, Ag, Au, formed so as to be adjacent to thecurrent confining layer and at least one of the fixed magnetizationlayer and the free magnetization layer. If the metallic layer is formedbetween the current confining layer and the fixed magnetization layer,the metallic layer functions as a supplier for the current confiningpath of the current confining layer and a protective layer for an oxide,a nitride and an oxynitride contained in the current confining layeragainst the fixed magnetization layer. If the metallic layer is formedbetween the current confining layer and the free magnetization layer,the metallic layer functions as a protective layer for an oxide, anitride and an oxynitride contained in the current confining layeragainst the fixed magnetization layer.

According to the aspects of the present invention can be provided amagneto-resistance effect element, that is, a CCP-CPP element which canenhance the MR ratio. Then, according to the aspects of the presentinvention can be provided a magnetic head with good reproducingcharacteristics, a magnetic disk device and a magnetic memory whichutilize the CCP-CPP element.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an embodiment of themagneto-resistance effect element according to the present invention.

FIG. 2A relates to an explanatory view for the enhancement of the MReffect by the insertion of a functional layer in the magneto-resistanceeffect element in FIG. 1.

FIG. 2B also relates to an explanatory view for the enhancement of theMR effect by the insertion of a functional layer in themagneto-resistance effect element in FIG. 1.

FIG. 3 is a cross sectional view relating to an modified embodiment fromthe magneto-resistance effect element in FIG. 1.

FIG. 4 is a schematic view illustrating a film forming apparatus formanufacturing the magneto-resistance effect element in FIG. 1.

FIG. 5 is a flow chart in a method for manufacturing themagneto-resistance effect element in FIG. 1.

FIG. 6 is a cross sectional view showing the state where themagneto-resistance effect element in FIG. 1 is incorporated in amagnetic head.

FIG. 7 is another cross sectional view showing the state where themagneto-resistance effect element in FIG. 1 is incorporated in amagnetic head.

FIG. 8 is a perspective view illustrating an essential part of amagnetic recording/reproducing device according to the presentinvention.

FIG. 9 is an enlarged perspective view illustrating the magnetic headassembly of the magnetic recording/reproducing device.

FIG. 10 is a view illustrating a magnetic memory matrix according to thepresent invention.

FIG. 11 is a view illustrating another magnetic memory matrix accordingto the present invention.

FIG. 12 is a cross sectional view illustrating an essential part of themagnetic memory.

FIG. 13 is a cross sectional view of the magnetic memory illustrated inFIG. 12, taken on line “A-A′”.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be described (Magneto-resistanceeffect element)

FIG. 1 is a perspective view illustrating a magneto-resistance effectelement (CCP-CPP type element) according to an embodiment of the presentinvention. Some or all components throughout the drawings in the presentapplication are schematically illustrated so that the illustratedthickness ratio for the components is different from the real thicknessratio for the components.

The magneto-resistance effect element illustrated in FIG. 1 includes amagneto-resistance effect element 10, a top electrode 11 and a bottomelectrode 20 which are disposed so as to sandwich the magneto-resistanceeffect element 10. Herein, the illustrated stacking structure is formedon a base (not shown).

The magneto-resistance effect element 10 includes an underlayer 12, apinning layer 13, a pinned layer 14, a bottom metallic layer 15, acurrent confining layer 16 (an insulating layer 161 and a currentconfining path 162), a top metallic layer 17, a free layer 18 and a caplayer 19 which are subsequently stacked and formed. Among them, the topmetallic layer 15, the current confining layer 16 and the top metalliclayer 17 constitute the spacer layer. Then, the pinned layer 14, thebottom metallic layer 15, the current confining layer 16, the topmetallic layer 17 and the free layer 18 constitute a spin dependentscattering unit (spin valve film) which is configured such that thenon-magnetic spacer layer is sandwiched between the two ferromagneticlayers. For clarifying the structural feature of the magneto-resistanceeffect element, the current confining layer 16 is represented under thecondition that the current confining layer 16 is separated from theupper and lower layers (the bottom metallic layer 15 and the topmetallic layer 17). Then, the components of the magneto-resistanceeffect element will be described.

<Electrode>

The bottom electrode 11 functions as an electrode for flowing a currentin the direction perpendicular to the spin valve film. In real, thecurrent can be flowed through the spin valve film in the directionperpendicular to the film surface thereof by applying a voltage betweenthe bottom electrode 11 and the top electrode 20. The change inresistance of the spin valve film originated from the magneto-resistanceeffect can be detected by utilizing the current. In other words, themagnetization detection can be realized by the current flow. The bottomelectrode 11 is made of a metallic layer with a relatively smallelectric resistance for flowing the current to the magneto-resistanceeffect element sufficiently.

The top electrode 20 also functions as an electrode for flowing acurrent in the direction perpendicular to the spin valve film in thesame manner as the bottom electrode 11. In real, the current can beflowed through the spin valve film in the direction perpendicular to thefilm surface thereof by applying a voltage between the bottom electrode11 and the top electrode 20. The top electrode can be made of a materialwith low resistance such as Cu, Au.

<Underlayer>

The underlayer 12 may be composed of a buffer layer 12 a and a seedlayer 12 b. The buffer layer 12 a can be employed for the compensationof the surface roughness of the bottom electrode 11. The seed layer 12 bcan be employed for controlling the crystalline orientation and thecrystal grain size of the spin valve film to be formed on the underlayer12.

The buffer layer 12 a may be made of Ta, Ti, W, Zr, Hf, Cr or an alloythereof. The thickness of the buffer layer 12 a is preferably set within1 to 10 nm, more preferably set within 2 to 5 nm. If the buffer layer 12a is formed too thin, the buffer layer 12 a can exhibit the inherentbuffering effect. If the buffer layer 12 a is formed too thick, theSeries resistance not contributing to the MR is increased. If the seedlayer 12 b can exhibit the buffering effect, the buffer layer 12 a maybe omitted. In a preferable example, the buffer layer 12 a is made of aTa layer with a thickness of 3 nm.

The seed layer 12 b may be made of any material controllable for thecrystalline orientation of (a) layer (s) to be formed thereon. Forexample, the seed layer 12 b may be made preferably of a metallic layerwith a fcc-structure (face-centered cubic structure), a hcp-structure(hexagonal close-packed structure) or a bcc-structure (body-centeredcubic structure).

Concretely, the seed layer 12 b may be made of Ru with hcp-structure orNiFe with fcc-structure so that the crystalline orientation of the spinvalve film to be formed thereon can be rendered an fcc (111) facedorientation. The crystalline orientation of the pinning layer 13 (e.g.,made of PtMn) can be rendered an fct (111)-structure (face-centeredtetragonal structure)-regulated orientation. If the magnetic layer ismade of a fcc-structured metal, the orientation of the magnetic layercan be rendered fcc (111) orientation under good condition. If themagnetic layer is made of a bcc-structured metal, the orientation of themagnetic layer can be rendered bcc (110) orientation.

In order to exhibit the inherent seeding function of the seed layer 12 bof enhancing the crystalline orientation sufficiently, the thickness ofthe seed layer 12 b is set preferably within 1 to 5 nm, more preferablywithin 1.5 to 3 nm. Ina preferable example, the seed layer 12 b may bemade of a Ru layer with a thickness of 2 nm.

The crystalline orientation for the spin valve film and the pinninglayer 13 can be measured by means of X-ray diffraction. For example, theFWHMs (full width at half maximum) in X-ray rocking curve of the fcc(111) peak of the spin valve film, the fct (111) peak or the bcc (110)peak of the pinning layer 13 (PtMn) can be set within a range of 3.5 to6 degrees, respectively under good crystallinity. The dispersion of theorientation relating to the spin valve film and the pinning layer can berecognized by means of diffraction spot using cross section TEM.

The seed layer 12 b may be made of a NiFe-based alloy (e.g.,Ni_(X)Fe_(100-X): X=90 to 50%, preferably 75 to 85%) layer of aNiFe-based non-magnetic ((Ni_(X)Fe_(100-X))_(100-Y)X_(Y): X═Cr, V, Nb,Hf, Zr, Mo)) layer. In the latter case, the addition of the thirdelement “X” renders the seed layer 12 b non-magnetic. The crystallineorientation of the seed layer 12 b of the NiFe-based alloy can beenhanced easily so that the FWHM in X-ray rocking curve can be renderedwithin a range of 3 to 5 degrees.

The seed layer 12 b functions not only as the enhancement of thecrystalline orientation, but also as the control of the crystal grainsize of the spin valve film. Concretely, the crystal grain size of thespin valve film can be controlled within a range of 5 to 20 nm so thatthe fluctuation in performance of the magneto-resistance effect elementcan be prevented, and thus, the higher MR ratio can be realized eventhough the magneto-resistance effect element is downsized.

The crystal grain size of the spin valve film can be determined on thecrystal grain size of the layer formed between the seed layer 12 b andthe spacer layer 16 by means of cross section TEM. In the case of abottom type spin valve film where the pinning layer 14 is located belowthe spacer layer 16, the crystal grain size of the spin valve film canbe determined on the crystal grain size of the pinning layer 13(antiferromagnetic layer) or the pinned layer 14 (fixed magnetizationlayer) to be formed on the seed layer 12 b.

With a reproducing head in view of high recording density, the elementsize is set to 100 nm or below, for example. Therefore, if the crystalgrain size is set larger for the element size, the elementcharacteristics may be fluctuated. In this point of view, it is notdesired that the crystal grain size of the spin valve film is set largerthan 20 nm.

Too large crystal grain size may cause the decrease of the number ofcrystal grain per element surface so as to cause fluctuation incharacteristics of the reproducing head. With the CCP-CPP elementforming a current confining path, it is not desired to increase thecrystal grain size than a prescribed grain size.

In contrast, large crystal grain size may decrease electron irregularreflection at grain boundary or inelastic scattering site. In this pointof view, in order to realize the large MR ratio, it is desired toincrease the crystal grain size at least up to 5 nm or over. Therequirement to realize the large MR ratio is inconsistent with therequirement to realize the prevention of the fluctuation in elementcharacteristics so that the requirement of the large MR ratio satisfiesthe trade-off relation with the requirement of the prevention of thefluctuation in element characteristics. Therefore, in view of thetrade-off relation, the crystal grain size is set preferably within 5 to20 nm.

In order to set the crystal grain size within 5 to 20 nm, the seed layer12 b may be made of a Ru layer with a thickness of 2 nm or a NiFe-basednon-magnetic ((Ni_(X)Fe_(100-X))_(100-Y)X_(Y): X═Cr, V, Nb, Hf, Zr, Mo,preferably y=0 to 30%)) layer. Too thick seed layer 12 b may cause theincrease of the Series resistance and rough the interface of the spinvalve film. Only if the seed layer 12 b can exhibit the inherentperformance under the condition that the crystal grain size of theCCP-CPP element can be miniaturized, the seed layer 12 b may be made ofanother material.

<Pinning Layer>

The pinning layer 13 functions as applying the unidirectional anisotropyto the ferromagnetic layer to be the pinned layer 14 on the pinninglayer 13 and fixing the magnetization of the pinned layer 14. Thepinning layer 13 may be made of an antiferromagnetic material such asPtMn, PdPtMn, IrMn, RuRhMn, FeMn, NiMn. In view of the use of theelement as a high density recording head, the pinning layer 13 ispreferably made of IrMn because the IrMn layer can apply theunidirectional anisotropy to the pinned layer 14 in comparison with thePtMn layer even though the thickness of the IrMn layer is smaller thanthe thickness of the PtMn layer. In this point of view, the use of theIrMn layer can reduce the gap width of the intended element for highdensity recording.

In order to apply the unidirectional anisotropy with sufficientintensity, the thickness of the pining layer 13 is appropriatelycontrolled. In the case that the pinning layer 13 is made of PtMn orPdPtMn, the thickness of the pinning layer 13 is set preferably within 8to 20 nm, more preferably within 10 to 15 nm. In the case that thepinning layer 13 is made of IrMn, the unidirectional anisotropy can beapplied even though the thickness of the pinning layer 13 of IrMn is setsmaller than the thickness of the pinning layer 13 of PtMn. In thispoint of view, the thickness of the pinning layer 13 of IrMn is setpreferably within 4 to 18 nm, more preferably within 5 to 15 nm. Inapreferred embodiment, the thickness of the IrMn pinning layer 13 is setto 7 nm.

The pinning layer 13 may be made of a hard magnetic layer instead of theantiferromagnetic layer. For example, the pinning layer 13 may be madeof CoPt (Co=50 to 85%), (CoPt_(100-X))_(100-Y)Cr_(Y): X=50 to 85%, Y=0to 40%) or FePt (Pt=40 to 60%). Since the hard magnetic layer has asmaller specific resistance, the Series resistance and the arearesistance RA of the element can be reduced.

<Pinned Layer: Fixed Magnetization Layer>

The pinned layer (fixed magnetization layer) 14 is formed as a syntheticpinned layer composed of the bottom pinned layer 141 (e.g., Co₉₀Fe₁₀ 3.5nm), the magnetic coupling layer 142 (e.g., Ru) and the top pinned layer143 (e.g., Fe₅₀Co₅₀ 1 nm/Cu 0.25 nm×2/Fe₅₀Co₅₀ 1 nm). The pinning layer13 (e.g., IrMn layer) is coupled via magnetic exchange with the bottompinned layer 141 formed on the pinning layer 13 so as to apply theunidirectional anisotropy to the bottom pinned layer 141. The bottompinned layer 141 and the top pinned layer 143 which are located underand above the magnetic coupling layer 142, respectively, are stronglymagnetically coupled with one another so that the direction ofmagnetization in the bottom pinned layer 141 becomes anti-paralleled tothe direction of magnetization in the top pinned layer 143.

The bottom pinned layer 141 may be made of Co_(X)Fe_(100-X) alloy (X=0to 100), Ni_(X)Fe_(100-X) (X=0 to 100) or an alloy thereof containing anon magnetic element. The bottom pinned layer 141 may be also made of asingle element such as Co, Fe, Ni or an alloy thereof.

It is desired that the magnetic thickness (saturated magnetizationBs×thickness t (Bs·t)) of the bottom pinned layer 141 is set almostequal to the one of the top pinned layer 143. Namely, it is desired thatthe magnetic thickness of the top pinned layer 143 corresponds to themagnetic thickness of the bottom pinned layer 141. For example, when thetop pinned layer 143 of Fe₅₀Co₅₀ 1 nm/Cu 0.25 nm×2/Fe₅₀Co₅₀ 1 nm isemployed, the magnetic thickness of the top pinned layer 143 is set to2.2 T×3 nm=6.6 Tnm because the saturated magnetization of the top pinnedlayer 143 is about 2.2 T. When the bottom pinned layer 141 of Co₉₀Fe₁₀is employed, the thickness of the bottom pinned layer 141 is set to 6.6Tnm/1.8 T=3.66 nm for the magnetic thickness of 6.6 Tnm because thesaturated magnetization of Co₉₀Fe₁₀ is about 1.8 T. In this point ofview, it is desired that the thickness of the bottom pinned layer 141made of Co₉₀Fe₁₀ is set to about 3.6 nm. When the bottom pinned layer141 of Co₇₅Fe₂₅ is employed, it is desired that the thickness of thebottom pinned layer 141 is set to about 3.3 nm on the same calculation.

The thickness of the bottom pinned layer 141 is preferably set within 2to 5 nm in view of the magnetic strength of the unidirectionalanisotropy relating to the pinning layer 13 (e.g., IrMn layer) and themagnetic strength of the antiferromagnetic coupling between the bottompinned layer 141 and the top pinned layer 143 via the magnetic couplinglayer 142 (e.g., Ru layer). Too thin bottom pinned layer 141 causes thedecrease of the MR ratio because the thickness of the top pinned layer143 is also decreased. In contrast, too thick bottom pinned layer 141causes the difficulty of obtaining the unidirectional anisotropymagnetic field requiring for the operation of the element. In apreferred embodiment, the bottom pinned layer 141 may be made of aCo₇₅Fe₂₅ layer with a thickness of 3.3 nm.

The magnetic coupling layer 142 (e.g., Ru layer) causes theantiferromatic coupling between the bottom pinned layer 141 and the toppinned layer 143 which are located under and above the magnetic couplinglayer 142, thereby constituting the synthetic pinned structure. In thecase that the magnetic coupling layer 142 is made of the Ru layer, thethickness of the Ru layer is preferably set within 0.8 to 1 nm. Only ifthe antiferromagnetic coupling between the pinned layers located underand above the magnetic coupling layer 142 can be generated, the magneticcoupling layer 142 may be made of another material except Ru or thethickness of the magnetic coupling layer 142 may be varied within 0.3 to0.6 nm instead of the thickness range of 0.8 to 1 nm. The formerthickness range of 0.3 to 0.6 nm corresponds to the first peak of RKKY(Runderman-Kittel-Kasuya-Yoshida), and the latter thickness range of 0.8to 1 nm corresponds to the second peak of RKKY. With the thickness rangeof the first peak of RKKY, the magnetic coupling layer 142 can exhibitan extremely large antiferromagnetic fixing strength, but the allowablethickness range of the magnetic coupling layer 142 is reduced. In apreferred embodiment, the magnetic coupling layer 142 may be made of theRu layer with a thickness of 0.9 nm so as to realize theantiferromagnetic coupling for the pinned layers stably.

The top pinned layer 143 may be made of Fe₅₀Co₅₀ 1 nm/Cu 0.25nm×2/Fe₅₀Co₅₀ 1 nm. The top pinned layer 143 composes the spin dependentscattering unit. The top pinned layer 143 can contribute directly to theMR effect, and thus, the material and thickness of the top pinned layer143 are important so as to realize a large MR ratio. The magneticmaterial of the top pinned layer 143 to be positioned at the interfacefor the current confining layer 16 is important in view of thecontribution of the spin dependent interface scattering.

Then, in the case of the top pinned layer 143 of the Fe₅₀Co₅₀ layer withbcc-structure, since the spin dependent interface scattering isenhanced, the MR ratio can be enhanced. As the FeCo-based alloy withbcc-structure, a Co_(X)Fe_(100-X) alloy (X=30 to 100) or a similarCoFe-based alloy containing an additive element can be exemplified.Among them, a Fe₄₀Co₆₀ alloy through a Fe₈₀Co₂₀ alloy may be employed inview of the above-described requirements.

In the case that the top pinned layer 143 is made of the magnetic layerwith bcc-structure easily exhibiting the large MR ratio, the thicknessof the top pinned layer 143 is preferably set to 1.5 nm or over so as tomaintain the bcc-structure thereof stably. Since the spin valve film ismade mainly of a metallic material with fcc-structure or fct-structure,only the top pinned layer 143 may have the bcc-structure. In this pointof view, too thin top pinned layer 143 can not maintain thebcc-structure thereof stably so as not to obtain the large MR ratio.

Herein, the top pinned layer 143 is made of the Fe₅₀Co₅₀ layers and theextremely thin Cu layers. The total thickness of the Fe₅₀Co₅₀ layers is3 nm and each Cu layer is formed on the corresponding Fe₅₀Co₅₀ layerwith a thickness of 1 nm. The thickness of the Cu layer is 0.25 nm andthe total thickness of the top pinned layer 143 is 3.5 nm.

The MR ratio becomes large as the thickness of the top pinned layer 143is increased. In contrast, the pinning magnetic field becomes large asthe thickness of the top pinned layer 143 is increased. Therefore, theMR ratio and the pinning magnetic field satisfies the trade-off relationone another. For example, if the top pinned layer is made of an FeCoalloy layer with bcc-structure is employed, the thickness of the toppinned layer is set preferably to 1.5 nm or over so as to realize thelarge MR ratio. In contrast, the thickness of the top pined layer is setto preferably to 5 nm or below, more preferably to 4 nm or below. As aresult, the preferable thickness range of the top pinned layer 143 isset preferably within 1.5 to 5 nm, more preferably within 2 to 4 nm.

The top pinned layer 143 may be made of a Co₉₀Fe₁₀ alloy withfcc-structure or a Co alloy with hcp-structure which used to be widelyemployed for a conventional magneto-resistance effect element, insteadof the magnetic material with the bcc-structure. The top pinned layer143 can be made of a single element such as Co, Fe, Ni or an alloycontaining at least one element selected from the group consisting ofCo, Fe, Ni. In view of the large MR ratio of the top pinned layer 143,the FeCo alloy with the bcc-structure, the Co alloy containing Coelement of 50% or over and the Ni alloy containing Ni element of 50% orover are in turn preferable.

The top pinned layer 143 may be made of a Heusler alloy such as Co MnGe,CoMnSi, Co MnAl.

In this embodiment, the top pinned layer 143 is made of the magneticlayers (FeCo layers) and the non magnetic layers (extremely thin Culayers) which are alternately stacked respectively. In this case, thetop pinned layer 143 can enhance the spin dependent scattering effectwhich is also called as a “spin dependent bulk scattering effect”,originated from the extremely thin Cu layers.

The spin dependent bulk scattering effect is utilized in pairs for thespin dependent interface scattering effect. The spin dependent bulkscattering effect means the occurrence of an MR effect in a magneticlayer and the spin dependent interface scattering effect means theoccurrence of an MR effect at an interface between a spacer layer and amagnetic layer.

Hereinafter, the enhancement of the bulk scattering effect of thestacking structure of the magnetic layer and the nonmagnetic layer willbe described. With the CCP-CPP element, since a current is confined inthe vicinity of the current confining layer 16, the resistance in thevicinity of the current confining layer 16 contributes the totalresistance of the magneto-resistance effect element. Namely, theresistance at the interface between the current confining layer 16 andthe magnetic layers (pinned layer 14 and the free layer 18) contributeslargely to the magneto-resistance effect element. That means thecontribution of the spin dependent interface scattering effect becomeslarge and important in the CCP-CPP element. The selection of magneticmaterial located at the interface for the current confining layer 16 isimportant in comparison with a conventional CPP element. In this pointof view, the pinned layer 143 is made of the FeCo alloy with thebcc-structure exhibiting the large spin dependent interface scatteringeffect as described above.

However, it may be that the spin dependent bulk scattering effect shouldbe considered so as to develop the MR ratio. In view of the developmentof the spin dependent bulk scattering effect, the thickness of the thinCu layer is set preferably within 0.1 to 1 nm, more preferably within0.2 to 0.5 nm. Too thin Cu layer can not develop the spin dependent bulkscattering effect sufficiently. Too thick Cu layer may reduce the spindependent bulk scattering effect and weaken the magnetic couplingbetween the magnetic layers via the non magnetic Cu layer, which themagnetic layers sandwiches the non magnetic Cu layer, therebydeteriorating the property of the pinned layer 14. In a preferredembodiment, in this point of view, the thickness of the non-magnetic Culayer is set to 0.4 nm.

The non-magnetic layer sandwiched by the magnetic layers may be made ofHf, Zr, Ti instead of Cu. In the case that the pinned layer 14 containsthe non-magnetic layer (s), the thickness of the one magnetic layer suchas a FeCo layer which is separated by the non-magnetic layer is setpreferably within 0.5 to 2 nm, more preferably within 1 to 1.5 nm.

In the above embodiment, the top pinned layer 143 is constituted of thealternately stacking structure of FeCo layer and Cu layer, but may bemade of an alloyed layer of FeCo and Cu. The composition of theresultant FeCoCu alloy may be set to ((Fe_(X)Co_(100-X))_(100-Y)Cu_(Y):X=30 to 100% Cr, Y=3 to 15%), but set to another composition range. Thethird element to be added to the main composition of FeCo may beselected from Hf, Zr, Ti instead of Cu.

The top pinned layer 143 may be also made of a single element such asCo, Fe, Ni or an alloy thereof. In a simplified embodiment, the toppinned layer 143 may be made of an Fe₉₀Co₁₀ layer with a thickness of 2to 4 nm, as occasion demands, containing a third additive element.

In this embodiment, as shown in FIG. 1, the functional layers 21 made ofSi, Mg, B, Al are inserted (formed) into the bottom pinned layer 141 andthe top pinned layer 143. The functional layer 21 can exhibit adifferent function from the enhancement of spin dependent bulkscattering effect by the insertion of the non-magnetic layer made of Cuor the like in References 1 and 2. The functional layer 21 can exhibitthe large MR ratio only if the functional layer 21 is inserted in theCCP-GMR film of the CCP-CPP element. The functional layer 21 will bedescribed in detail, hereinafter.

In this embodiment, the functional layers 21 are formed in the bottompinned layer 141 and the top pinned layer 142, but may be formed ineither one of the bottom pinned layer 141 and the top pinned layer 142.Then, the functional layer(s) 21 may be formed at the interface betweenthe top pinned layer 143 and the bottom metallic layer of the spacerlayer, for example. Then, the functional layer (s) 21 may be formed inthe free layer and/or

<Spacer Layer>

Then, the spacer layer will be concretely described. The bottom metalliclayer 15 is employed for the formation of the current confining path 162and thus, functions as a supplier for the current confining path 162. Itis not required that the metallic layer 15 remains as it is apparentlyafter the formation of the current confining path 162. In this point ofview, the bottom metallic layer 15 functions broadly as a part of thespacer layer. The bottom metallic layer 15 functions as a stopper layerpreventing the oxidization of the magnetic layer 143 which is locatedbelow the current confining layer 16 in the formation of the currentconfining layer 16.

When the current confining path 162 is made of Cu, the bottom metalliclayer 15 is made preferably of the same material, Cu. When the currentconfining path 162 is made of a magnetic material, the pinned layer 14may be made of the same magnetic material or a different magneticmaterial. The current confining path 162 can be made of Au, Ag insteadof Cu.

The current confining layer 16 includes the insulating layer 161 and thecurrent confining path 162. The insulating layer 161 is made of oxide,nitride, oxynitride or the like. In order to exhibit the inherentfunction of the spacer layer, the thickness of the insulating layer 161is set preferably within 1 to 3 nm, more preferably within 1.5 to 2.5nm.

The current confining path 162 functions as a path to flow a current inthe direction perpendicular to the film surface of the current confininglayer 16 and then, confining the current. The current confining path 162also functions as a conductor to flow the current in the directionperpendicular to the film surface of the insulating layer 161 and ismade of a metal such as Cu. In other words, the spacer layer 16 exhibitsthe current-confined path structure (CCP structure) so as to enhance theMR ratio from the current confining effect. The current confining path162 (CCP) may be made of Au, Ag, Ni, Co, Fe or an alloy containing atleast one from the listed elements instead of Cu. In a preferredembodiment, the current confining path 162 is made of a Cu alloy. Thecurrent confining path 162 may be made of an alloy layer of CuNi, CuCoor CuFe. Herein, the content of Cu in the alloy is set preferably to 50%or over in view of the enhancement of the MR ratio and the reduction ofthe interlayer coupling field, Hin (interlayer coupling field) betweenthe pinned layer 14 and the free layer 18.

The content in oxygen and nitrogen of the current confining path 162 ismuch smaller than (at least half as large as) the one of the insulatinglayer 161. The current confining path 162 is generally crystallized.Since the resistance of the crystalline phase is smaller than theresistance of the non-crystalline phase, the current confining path 162can easily conduct the inherent function.

The top metallic layer 17 functions as a barrier layer protecting theoxidization of the free layer 18 to be formed thereon through thecontact with the oxide of the current confining layer 16 so that thecrystal quality of the free layer 18 cannot be deteriorated. Concretely,the top metallic layer 17 protects the free layer 18 to be formedthereon so as not to suffer from the oxidizing and nitriding through thecontact with the oxide, nitride and/or oxynitride of the currentconfining layer 16. Namely, the top metallic layer 17 prevents thedirect contact of the oxygen contained in the oxide of the currentconfining path 162 with the free layer 18. Then, when the insulatinglayer 161 is made of an amorphous material (e.g., Al₂O₃), the crystalquality of a metallic layer to be formed on the layer 161 may bedeteriorated, but when an extremely thin layer (e.g., Cu layer) todevelop the crystal quality of fcc-structure is provided, the crystalquality of the free layer 18 can be remarkably improved.

It is desired that the top metallic layer 17 is made of the samematerial (e.g., Cu) as the current confining path 162 of the currentconfining layer 16. If the top metallic layer 17 is made of a differentmaterial from the current confining path 162, the resistance at theinterface between the top metallic layer 17 and the current confiningpath 162 is increased, but if the top metallic layer 17 is made of thesame material from the current confining path 162, the resistance at theinterface between the top metallic layer 17 and the current confiningpath 162 is not increased. When the current confining path 162 is madeof a magnetic material, the pinned layer 14 may be made of the samemagnetic material or a different magnetic material. The currentconfining path 162 can be made of Au, Ag instead of Cu.

<Free Layer: Free Magnetization Layer>

The free layer 18 is a ferromagnetic layer of which the direction ofmagnetization is varied commensurate with the external magnetic field.For example, the free layer 18 is made of a double-layered structure ofCo₉₀Fe₁₀ 1 nm/Ni₈₃Fe₁₇ 3.5 nm. In order to realize the large MR ratio,it is desired to provide the CoFe alloy instead of the NiFe alloy. Then,in order to realize the large MR ratio, the selection of magneticmaterial of the free layer 18 in the vicinity of the spacer 16, that is,at the interface therebetween is important. The free layer 18 may bemade of a single Co₉₀Fe₁₀ layer with a thickness of 4 nm without a NiFelayer or a triple-layered structure of CoFe/NiFe/CoFe. As describedbelow, the free layer 18 may partially composes an amorphous alloy layermade of CoZrNb.

Among CoFe alloys, the Co₉₀Fe₁₀ layer is preferably employed in view ofthe stable soft magnetic property. If a CoFe alloy similar to theCo₉₀Fe₁₀ alloy in composition is employed, it is desired that thethickness of the resultant CoFe alloy layer is set within 0.5 to 4 nm.Moreover, the free layer 18 may be made of Co_(X)Fe_(100-X) (X=70 to90%).

Then, the free layer 18 is made of an alternately stacking structure ofCoFe layers or Fe layers with a thickness of 1 to 2 nm and extremelythin Cu layers with a thickness of 0.1 to 0.8 nm.

In the case that the current confining layer 16 is made of the Cu layer,it is desired that the FeCo layer with bcc-structure is employed as theinterface material thereof for the spacer layer 16 so as to enhance theMR ratio in the same manner as the pinned layer 14. As the FeCo layerwith bcc-structure, the Fe_(X)Co_(100-X) (X=30 to 100) or, as occasiondemands, containing a third additive element, may be employed. In apreferred embodiment, a Co₉₀Fe₁₀ 1 nm/Ni₈₃Fe₁₇ 3.5 nm may be employed.Instead of the FeCo layer with bcc-structure, a CoFe layer withfcc-structure may be employed.

The free layer 18 may partially composes an amorphous alloy layer madeof CoZrNb. In this case, it is required that the portion of the freelayer 18 adjacent to the spacer layer 16 is made of a crystallinemagnetic layer. The free layer 18 may be structured as (1) a singlecrystal layer, (2) a stacking structure of crystal layer/amorphous layerand (3) a stacking structure of crystal layer/amorphous layer/crystallayer, as viewed from the spacer layer 16. In these cases (1) to (3), itis important that the crystal layer of the free layer 18 is alwayscontacted with the spacer layer 16.

In this embodiment, as shown in FIG. 1, the functional layer 21containing Si, Mg, B, Al is inserted (formed) in the free layer 18. Thefunctional layer 21 can exhibit a different function from theenhancement of spin dependent bulk scattering effect by the insertion ofthe non-magnetic layer made of Cu or the like in References 1 and 2 asdescribed above (in pinned layer). The functional layer 21 can exhibitthe large MR ratio only if the functional layer 21 is inserted in theCCP-GMR film of the CCP-CPP element. The functional layer 21 will bedescribed in detail, hereinafter.

In this embodiment, the functional layer 21 is formed in the free layer18, but may be formed on the free layer 18 or at the interface betweenthe free layer 18 and the top metallic layer 17 of the spacer layer, forexample. Then, the functional layer(s) 21 may be formed in the freelayer and/or cap layer as described below.

<Cap Layer>

The cap layer 19 functions as protecting the spin valve film. The caplayer 19 may be made of a plurality of metallic layers, e.g., adouble-layered structure of Cu 1 nm/Ru 10 nm. The layered turn of the Culayer and the Ru layer may be switched so that the Ru layer is locatedin the side of the free layer 18. In this case, the thickness of the Rulayer is set within 0.5 to 2 nm. The exemplified structure isparticularly desired for the free layer 19 of NiFe because themagnetostriction of the interface mixing layer formed between the freelayer 18 and the cap layer 19 can be lowered due to the non-solutionbetween Ru and Ni.

When the cap layer 19 is made of the Cu/Ru structure or the Ru/Custructure, the thickness of the Cu layer is set within 0.5 to 10 nm andthe thickness of the Ru layer is set smaller, e.g., within 0.5 to 5 nmdue to the large specific resistance.

The cap layer 19 may be made of another metallic layer instead of the Culayer and/or the Ru layer. The structure of the cap layer 19 is notlimited only if the cap layer 19 can protect the spin valve film. If theprotective function of the cap layer 19 can be exhibited, the cap layer19 may be made of still another metal. Attention should be paid to themetallic layer because the kind of material of the cap layer may changethe MR ratio and the long reliability. In view of the stable MR ratioand long reliability, the Cu layer and/or the Ru layer is preferable forthe cap layer.

In this embodiment, as shown in FIG. 1, the functional layer 21containing Si, Mg, B, Al is inserted (formed) in the cap layer 19. Thefunctional layer 21 can exhibit a different function from theenhancement of spin dependent bulk scattering effect by the insertion ofthe non-magnetic layer made of Cu or the like in References 1 and 2 asdescribed above (in pinned layer). The functional layer 21 can exhibitthe large MR ratio only if the functional layer 21 is inserted in theCCP-GMR film of the CCP-CPP element. The functional layer 21 will bedescribed in detail, hereinafter.

In this embodiment, the functional layer 21 is formed in the cap layer19, but may be formed on the cap layer 19, that is, between the freelayer 18 and the cap layer 19, for example. Then, the functional layer(s) 21 may be formed in the pinned layer and/or free layer as describedabove.

In this embodiment, by inserting the functional layer (s) 21 containingat least one element selected from the group consisting of Si, Mg, B, Alinto at least one of the bottom pinned layer 141, the top pinned layer143, the free layer 18 and the cap layer 19, the MR ratio of themagneto-resistance effect element (CCP-CPP element) in FIG. 1 can beenhanced. In References 1 and 2, an intermediate layer similar to thefunctional layer is formed in the CCP-CPP element, thereby enhancing theMR ratio of the CCP-CPP element through the enhancement of the spindependent bulk scattering. In this embodiment, however, the enhancementof the MR ratio relating to the functional layer is not originated fromthe enhancement of spin dependent bulk scattering.

The inventors found out that if the functional layer made of Si isinserted in at least one of the bottom pinned layer 141, the top pinnedlayer 143, the free layer 18 and the cap layer 19, the MR ratio of themagneto-resistance effect element in FIG. 1 is enhanced. One concretefilm structure of the magneto-resistance effect element exhibiting theenhancement of the MR ratio will be described below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 Co₇₅Fe₂₅ 3.3 nm/Ru 0.9 nm/ Fe₅₀Co₅₀ 1nm/Cu 0.25 nm × 2/Fe₅₀Co₅₀ 1 nm Metallic layer 15 Cu 0.6 nm Currentconfining layer 16 Insulating layer 161 of Al₂O₃ and current confiningpath 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18 Co₆₀Fe₄₀ 2nm/Si 0.25 nm/ Ni₈₃Fe₁₇ 3.5 nm Cap layer 19 Cu 1 nm/Ta 2 nm/Ru 15 nm Topelectrode 20

In the CCP-GMR film of the above-listed film structure, the MR ratio was11%. If the free layer 18 is made of Co₄₀Fe₆₀ 2 nm/Ni₈₃Fe₁₇ 3.5 nmwithout the functional layer, the MR ratio was 9.5%. As a result, byinserting the Si layer into the free layer 18 of the CCP-GMR film, itwas confirmed that the MR ratio is enhanced by 1.5%.

In the film structure, it was confirmed that the insertion of the Sifunctional layer into the free layer 18 can enhance the MR ratio.Similarly, it was confirmed that the insertion of the Si functionallayer into the cap layer 19 and the pinned layer 14 can enhance the MRratio. The detail explanation will be done in Examples.

Herein, the reason of the enhancement of the MR ratio of themagneto-resistance effect element in this embodiment will be described.At present, the mechanism to develop the MR ratio may not be fullyrecognized.

A. Discussion for the mechanism relating to the enhancement of the MRratio of the magneto-resistance effect element through the insertion ofthe functional layer. First of all, it is considered that theenhancement of the MR ratio and the reliability is originated from thecapturing effect of excess oxygen. FIG. 2A relates to a cross sectionalview of a conventional CCP-GMR film without a functional layer. In FIG.2A, since the insulating layer 161 is made of Al₂O₃, the excess oxygengenerated when the Al₂O₃ is formed is diffused into the pinned layer 14and the free layer 18.

When the excess oxygen is diffused into the pinned layer 14 and the freelayer 18, the excess oxygen may oxidize the magnetic constituentelements such as Co, Fe, Ni. If the CoO, FeO or NiO are formed in thepinned layer 14 and the free layer through the oxidation, the spindependent bulk scattering may be deteriorated. Moreover, if the CoO, FeOor NiO are formed at the interface between the pinned layer 14 and thebottom metallic layer 15 and at the interface between the top metalliclayer 17 and the free layer 18, the spin dependent interface scatteringmay be deteriorated. The reduction of the spin dependent bulk scatteringand the spin dependent interface scattering causes the reduction of theMR ratio. In this point of view, a conventional CCP-GMR film can notexhibit the inherent GMR effect sufficiently and in order to mount theCCP-GMR film at a magnetic head for high density recording magneticrecording device, it is effective to prevent the diffusion of the excessoxygen from the insulating layer 162.

FIG. 2B relates to a cross sectional view of the CCP-GMR film with afunctional layer inserted therein. In FIG. 2B, the Si functional layer21 is inserted into the top pinned layer 143. Table 1 lists variouselement oxide formation energies. In Table 1, the element with loweroxide formation energy means an element likely to be oxidized. Referringto Table 1, elemental Si is likely to be oxidized in comparison with Co,Fe, Ni. Therefore, the excess oxygen from the free layer 18 and thepinned layer 14 is shifted to the Si functional layer 21 so that theelemental Si is oxidized and the elemental Co, Fe, Ni are (is) reduced.Therefore, by inserting the Si functional layer into the top pinnedlayer 143 and the free layer 18, the formation of CoO, FeO and NiO canbe prevented so that the spin dependent bulk scattering and the spindependent interface scattering can not be deteriorated. As a result, theCCP-GMR film can exhibit the inherent GMR effect sufficiently.

TABLE 1 Oxide formation free energy Element Oxide {×10⁻⁶ J/kmol} Metalpass material Cu CuO −127 Magnetic material Co CoO −213 Ni NiO −216 FeFeO −244 Examples of element with Mo MoO₂ −502 higheroxygen affinitythan Mg MgO −573 magnetic material V VO₂ −680 W WO₃ −763 Si SiO₂ −805 TiTiO₂ −880 Zr ZrO₂ 1037 Cr Cr₂O₃ −1048 Hf HfO₂ −1084 B B₂O₃ −1170 AlAl₂O₃ −1580 Ta Ta₂O₅ −1970

In order to realize the enhancement of the MR ratio, it is required thatthe element to be employed for the functional layer is appropriatelyselected. As is apparent from Table 1, there are many elements likely tobe oxidized in comparison with Co, Fe Ni in addition to Si. For example,if the Ta or Hf functional layer is inserted into the pinned layer 14 orthe free layer 18, the Ta or Hf functional layer can exhibit the excessoxygen-capturing function in the same manner as the Si functional layer.With the Ta or Hf functional layer, however, the spin-polarizedconduction electrons may bring about some scatterings of nospin-dependent through the spin orbit interaction at the Ta or Hffunctional layer. In other words, even though the Ta or Hf functionallayer captures the excess oxygen so that the CPP-GMR film can exhibitthe inherent GMR effect sufficiently, the spin-polarized conductionelectrons can not reach the magnetic layer effectively and efficientlybecause the conduction electrons lose the inherent spin polarization atthe Ta or Hf layer. As a result, the CPP-GMR film can not exhibit theinherent GMR effect, resulting in the reduction of the MR ratio.

In contrast, since the elemental Si, the Si functional layer being ableto exhibit the enhancement of the MR effect, is an element of smalleratomic number, with the Si functional layer, the spin-polarizedconduction electrons may not bring about some scatterings of nospin-dependent through the spin orbit interaction in comparison with theTa or Hf functional layer. As a result, the Ta or Hf functional layermay not reduce the GMR effect of the CPP-GMR element in view of the spinpolarization. In this way, since the Si functional layer may not bringabout the scattering of no spin-dependent and may capture the excessoxygen, the Si functional layer can enhance the MR ratio of the CCP-GMRfilm. According to the above-described discussion, as an element likelyto be oxidized in comparison with Co, Fe and Ni, Mg, B and Al may beexemplified. It may be, therefore, that the Mg, B or Al functional layercan enhance the MR ratio of the CCP-GMR film through the capture of theexcess oxygen.

It is also considered that the enhancement of the MR ratio of theformation of the functional layer is originated from the diffusionpreventing effect in addition to the excess oxygen capturing effect.When the Mn elements of the pinning layer 13 and the Ni elements of thetop free layer are diffused near the current confining layer, theresistance of the current confining path may be increased and/or thespin dependent interface scattering may be reduced, resulting in thereduction of the MR ratio. In the magneto-resistance effect element, forexample, if the Si functional layer is inserted in the top pinned layer143, the diffusion of the Mn elements contained in the pinning layer 13can be prevented near the current confining layer 16 so as to enhancethe MR ratio of the CPP-GMR film. Moreover, when the free layer 18 ismade of Fe₄₀Co₆₀ 20 nm/Ni₈₃Fe₁₇ 35 nm, if the Si functional layer isformed in a thickness of 0.25 nm between the Fe₄₀Co₆₀ layer and theNi₈₃Fe₁₇, the diffusion of the Ni elements contained in the free layer18 is prevented, resulting in the enhancement of the MR ratio.

Even though the Si functional layer is inserted in the cap layer 19, theMR ratio can be enhanced, which will be referred to Examples,hereinafter. In this case, since the functional layer is not formedbetween the pinning layer and the current confining layer and betweenthe Ni-containing layer of the free layer and the current confininglayer, the functional layer can not exhibit the diffusion preventingfunction against the Mn elements and the Ni elements. As a result, thediffusion preventing function of the functional layer is not anessential function for the enhancement of the MR ratio.

It is considered that the enhancement of the MR ratio of the functionallayer is originated from the stabilization of the bcc-structure of thefree layer 18.

When the portion of the free layer 18 in the side of the spacer layer ismade of a magnetic material of bcc-structure, the spin dependentinterface scattering is increased so as to realize the large MR ratio.In view of the soft magnetic property, it is not desired that the freelayer 18 is made of a single layer of Fe₅₀Co₅₀ and it is desired thatthe free layer 18 is made of Fe₅₀Co₅₀ 2 nm/Ni₉₀Fe₁₀ 3.5 nm. In thelatter case, since the Fe₅₀Co₅₀ layer is formed thinner, thebcc-structure of the Fe₅₀Co₅₀ layer may become unstable because thefcc-structure of the Ni₉₀Fe₁₀ layer, which is formed on the Fe₅₀Co₅₀layer, affects the crystallinity of the Fe₅₀Co₅₀ layer. In this case, ifthe Si functional layer with a thickness of 0.25 nm is inserted betweenthe Fe₅₀Co₅₀ layer and the Ni₉₀Fe₁₀ layer, the Si functional layer cutsoff the lattice match between the Fe₅₀Co₅₀ layer and the Ni₉₀Fe₁₀ layer,allowing the stability of the bcc-structure of the Fe₅₀Co₅₀ layer.

As described above, however, even though the Si functional layer isinserted in the cap layer 19, the MR effect can be enhanced, so that thestabilization of the bcc-structure is not an essential function for theenhancement of the MR ratio.

Possibly, the enhancement of the MR ratio of the CCP-GMR film is mainlyoriginated from the capturing effect of the excess oxygen from thespacer layer. When the Si functional layer is formed between theFe₅₀Co₅₀ layer and the Ni₉₀Fe₁₀ layer, the enhancement of the MR ratioof the CCP-GMR film may be partially originated from the diffusionpreventing effect of the Ni elements and the stabilization of thebcc-structure of the Fe₅₀Co₅₀ layer. Anyway, if the functional layer isformed, the MR ratio of the CPP-GMR film can be enhanced.

The functional layer 21 may be made of a material containing an elementsuch as Mg, B, Al with an oxide formation energy lower than Co, Ni, Fe,in addition to Si. Since the non-magnetic functional layer 21 isinserted, the magnetic coupling of the pinned layer 14 or the free layer18 (that is, between the top magnetic layer and the bottom magneticlayer which are divided by the functional layer) may be divided. Inorder to maintain the magnetic coupling of the pinned layer 14 and thefree layer 18 via the functional layer 21 sufficiently, the thickness ofthe functional layer 21 is set preferably within 0.05 to 1 nm, morepreferably within 0.1 to 0.7 nm.

On the other hand, when the functional layer 21 is formed in the caplayer 19, the thickness of the functional layer 21 can be set largerthan in the case of the pinned layer 14 and the free layer 18 becausethe magnetic coupling is not required to be divided. Therefore, thethickness of the functional layer is set preferably within 0.05 to 3 nm,more preferably within 0.1 to 1 nm. Too thick functional layer may causethe increase of the Series resistance.

In the case that the functional layer 21 is formed in the pinned layer14 and the free layer 18, the functional layer 21 may be made of a layermixed with magnetic element such as Co, Ni, Fe and non-magnetic inherentfunctional element such as Si, Mg, B, Al. For example, in the case thatthe functional layer is inserted into the free layer 18 of Fe₅₀Co₅₀ 2nm/Ni₉₀Fe₁₀ 3.5 nm, the functional layer may be made of Fe₅₀Co₅₀containing additive Si or Ni₉₀Fe₁₀ containing additive Si. In this case,since the functional layer contains the magnetic elements and the Sielement, the Si elements may be dispersed in the thickness direction ofthe functional layer so that the capturing efficiency of excess oxygenmay be reduced, in comparison with the Si functional layer without themagnetic elements. However, since the functional layer is formed, theenhancement of the MR ratio can be increased to some degrees. Withoutthe functional layer, the enhancement of the MR ratio can not beincreased. Moreover, since the functional layer containing the magneticelements and the Si element is formed, the magnetic coupling of themagnetic layer (that is, the top magnetic layer and the bottom magneticlayer which are divided by the functional layer) can be easilymaintained via the functional layer.

Suppose that the Si elements are dispersed entirely in the free layer 18of FeCo/NiFe, the free layer 18 becomes FeCoSi/NiFeSi. In this case,since the Si elements to capture the excess oxygen are disperseduniformly in the free layer 18, the capturing effect of the excessoxygen may be diminished because the excess oxygen can not be gather up.In other words, in order to achieve the present invention, it isrequired that the Si elements are added to the magnetic layer as thefunctional layer, and not required that the Si elements are added as itis.

It is not desired that the functional layer is formed remote from thespacer layer. If the functional layer is formed remote from the spacerlayer, the functional layer can not capture the excess oxygen of theportions of the pinned layer 14 and the free layer 18 in the vicinity ofthe spacer layer so that the excess oxygen remains in the magnetic layermost contributing the MR effect in the vicinity of the current confininglayer 16. In the case that the functional layer 21 is inserted in thepinned layer 14, it is desired that the functional layer 21 is formed inthe region remote from the interface between the pinned layer 14 and thespacer layer by 10 nm or below in the direction from the interfacetherebetween to the pinned layer 14. In the case that the functionallayer 21 is inserted in the free layer 18 and the cap layer 19, it isdesired that the functional layer 21 is formed in the region remote fromthe interface between the free layer 18 and the spacer layer by 10 nm orbelow in the direction from the interface therebetween to the free layer18.

The functional layers may be formed in the pinned layer 14, the freelayer 18 and the cap layer 19. In this case, the layers can berepresented as Fe₅₀Co₅₀ 2 nm/first functional layer Si 0.25 nm/Ni₉₀Fe₁₀1.5 nm/second functional layer Si 0.25 nm/Ni₉₀Fe₁₀ 1 nm/third functionallayer Si 0.25 nm/Ni₉₀Fe₁₀ 1 nm. The distance of the first functionallayer and the second functional layer is set preferably within 1 to 2nm, and the distance of the second functional layer and the thirdfunctional layer is set preferably within 1 to 2 nm.

If the functional layers are formed, the capturing effect of excessoxygen can be enhanced. The functional layers are formed both of oreither of the pinned layer 14 and the free layer 18.

On the other hand, if the functional layers are formed in the magneticlayer, the magnetic coupling of the magnetic layer is reduced so thatthe magnetic characteristics of the magnetic layer may be deteriorated.In order to prevent the deterioration of the magnetic coupling in thepinned layer 14 or the free layer, the total thickness of the functionallayers is preferably set to the thickness of one functional layer. Thedistance between the adjacent functional layers is set within 1 to 2 nm.

The MR ratio is increased dependent on the kind of material of themagnetic layer. The MR ratio is increased as the Fe composition ratio isincreased. One film structure embodiment will be listed below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 Co₇₅Fe₂₅ 3.3 nm/Ru 0.9 nm/ Fe₅₀Co₅₀ 1nm/Cu 0.25 nm × 2/Fe₅₀Co₅₀ 1 nm Metallic layer 15 Cu 0.6 nm Currentconfining layer 16 Insulating layer 161 of Al₂O₃ and current confiningpath 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18 described laterCap layer 19 Cu 1 nm/Ta 2 nm/Ru 15 nm Top electrode 20

In comparison of the free layer 18 of Fe—Co 2 nm/Si 0.25 nm/Ni₈₃Fe₁₇ 3.5nm (with the functional layer 21) with the free layer 18 of FeCo 2nm/Ni₈₃Fe₁₇ 3.5 nm (without the functional layer 21), the MR ratio isincreased by 0.5% at the Fe composition of 10 at. % at the interfacebetween the free layer 18 and the spacer, and by 1.5% at the Fecomposition of 40 at. % thereat, and by 2.2% at the Fe composition of 50at. % thereat.

It is apparent, therefore, that the MR ratio due to the functional layeris increased as the Fe composition is increased. In this point of view,in the case that the functional layer 21 is inserted in the magneticlayer, it is desired in view of the enhancement of the MR ratio that theFe composition is set to 10 at % or over in the region remote from thespacer layer by 1 nm or below, preferably to 40 at % or over therein.

The reason the MR ratio is increased as the Fe composition is increasedcan be considered as follows. The oxide formation energy of Fe is lowestamong Co, Fe, Ni. When the pinned layer 14 and the free layer 18 aremade of materials with Fe-rich compositions, the pinned layer 14 and thefree layer 18 are likely to be oxidized from the excess oxygen of thespacer layer. Therefore, the MR ratio of the CPP-GMR film subject to theexcess oxygen becomes lower than the MR ratio of the CPP-GMR film notsubject to the excess oxygen. However, in the CPP-GMR film subject tothe excess oxygen, the MR ratio can be easily increased by the capturingeffect of excess oxygen due to the formation of the Si functional layer.Among Co, Fe, Ni, the oxide formation energy of Fe is lowest and theoxide formation energy of Co is highest. Therefore, the MR ratio in themagnetic layer with higher Fe composition can be increased remarkably bythe formation of the functional layer 21 in comparison with the MR ratioin the magnetic layer with higher Ni composition and Co composition.

The structure of the magneto-resistance effect film 10 containing thefunctional layer therein can be observed by means of a three-dimensionalatom probe, e.g., the Local Electrode Atom Probe made by “ImagoScientific Instruments Inc”.

According to the three-dimensional atom probe, the composition of thematerial to be observed can be mapped three-dimensionally in the orderof atomic level. Concretely, the sample to be measured is processed inneedle shape so that the curvature radius of the forefront of the sampleis set within 30 to 100 nm and the length (height) of the sample is setto about 100 μm. Then, a high voltage is applied to the sample so as toevaporate the atoms from the forefront of the sample by means of theelectric field generated by the application of the high pulsed voltage,which the evaporated atoms are detected by the two-dimensional detector.The intended three-dimensional (x, y, z) structure can be obtained fromthe information in the depth (z-axis) direction by following the changesin position information of the atoms in the two dimensional (x, y) planewith time, which the position information of the atoms are detected bythe two-dimensional detector.

A three-dimensional atom probe made by “Oxford Instruments Inc.” orCameca Inc. may be employed instead of the three-dimensional atomicforce microprobe. The electric field evaporation may be conducted by theapplication of a laser pulse instead of the pulsed voltage. In bothcases, a biasing electric field is applied by means of DC voltage. Withthe pulsed voltage, the electric field requiring the electric fieldevaporation can be generated in dependent on the amplitude of thevoltage. With the laser pulse, the sample is locally heated by theirradiation of the laser pulse so that the electric field evaporationcan be likely to be generated.

The structure of the magneto-resistance effect film 10 containing thefunctional layer therein can be locally observed by means of elementanalysis through EDX in the cross sectional TEM image.

In this embodiment, as shown in FIG. 1, although the functional layersare applied for the bottom-type CCP-CPP element, the functional layersmay be applied for the top-type CCP-CPP element. FIG. 3 relates to across sectional view of a top type CCP-CPP element. In this case, thefunctional layer 21 may be formed in the underlayer 12 instead of thecap layer 19 in the bottom type CCP-CPP element. Then, the CCP-CPPelement will be described in comparison with another embodiment.

C. Comparison with a Metal CPP-GMR Film Containing a Si Functional Layer

In the metal CPP-GMR film, by inserting the Cu layer in the magneticlayer, the spin dependent bulk scattering is increased so as to enhancethe MR ratio, which is disclosed in “H. Yuasa et al., J. Appl. Phys.92(5), 2646 (2002)”. Then, in the metal CPP-GMR film, by inserting theB, Al or Si layer in the magnetic layer, instead of the Cu layer, the MRratio is increased which are disclosed in References 1 and 2.Hereinafter, the CCP-CPP film containing the Si functional layer thereinwill be described in comparison with the metal CPP-GMR film.

In the metal CPP-GMR film, the MR ratio can be enhanced by the formationof the inserting layer originated from the spin bulk scattering effect.Generally, the spin dependent bulk scattering is originated fromelemental Cu so that in the metal CPP-GMR film, the MR ratio can be mostenhanced by the formation of the Cu layer. Concretely, in the metalCPP-GMR film, the MR ratio from the formation of the Si, B or Al layeris one-fourth as large as the MR ratio from the formation of the Culayer.

Therefore, in the CCP-GMR film, the spin dependent bulk effect can beenhanced by the formation of the inserting layer. In fact, if the Culayer is inserted in the top pinned layer 143 so that the structure ofthe top pinned layer 143 is defined as Fe₅₀Co₅₀ 1 nm/Cu 2.5 nm/Fe₅₀Co₅₀1 nm/Cu 2.5 nm/Fe₅₀Co₅₀ 1 nm, the spin dependent bulk scattering effectcan be enhanced. However, the MR ratio of the CCP-GMR film is increasedby about 1% through the formation of the Cu layer and the MR ratio ofthe CCP-GMR film is increased by about 1.5% or over through theformation of the Si layer, which is contrary to the case of the metalCPP-GMR film containing the Cu layer and the Si layer therein.Therefore, the cause of the MR enhancement through the formation of theSi layer in the CCP-GMR film is different from the cause of the MRenhancement through the formation of the Si layer in the metal CPP-GMRfilm so that the large MR enhancement through the formation of the Silayer in the CCP-GMR film is a specific feature.

The reason the MR enhancement effect through the formation of the Silayer in the CCP-GMR film is different from the MR enhancement effectthrough the formation of the Si layer in the metal CPP-GMR film isoriginated from that the MR enhancement effect of the CCP-GMR elementcan be obtained by forming the Si layer in the cap layer. On the otherhand, since the MR enhancement effect of the metal CPP-GMR element cannot be obtained by forming the Si layer in the cap layer through thespin dependent bulk scattering.

As described above, the cause that the MR of the metal CPP-GMR filmthrough the formation of the Si layer is not increased in comparisonwith the CCP-GMR film is originated from that in the metal CPP-GMR film,since the excess oxygen does not remain in the magnetic layer withoutthe spacer layer as a supplier of the excess oxygen, the metal CCP-GMRfilm can exhibit the inherent MR ratio sufficiently through the spindependent bulk and interface scatterings. In contrast, in the CCP-GMRfilm, since the excess oxygen remains in the magnetic layer, the CCP-GMRfilm can not exhibit the inherent MR ratio sufficiently so that in theCCP-GMR film, the MR ratio can be enhanced by the formation of the Silayer under the capturing effect of the excess oxygen. In this case, thespin dependent scattering effect can be recovered.

In this way, by utilizing the capturing effect of the excess oxygenthrough the Si Mg, B or Al functional layer in the CCP-GMR film, the MRratio of the CCP-GMR film can be enhanced.

D. Application of a Functional Layer for a TMR Film

The functional layer may be applied for a TMR film so as to enhance theMR ratio. The TMR film can be structured as substituting the spacerlayer of metallic layer 15/current confining layer 16/metallic layer 17with an insulating layer. In the TMR film, the insulating layer is madeof e.g., MgO or Al₂O₃. In the TMR film, the spin polarizations of thepinned layer 14 and the free layer 18 are considered for the MR. Thespin polarization is lowered by the diffusion of the excess oxygen ofthe MgO or Al₂O₃ into the pinned layer 14 and the free layer 18. In theTMR film, therefore, the prevention of the reduction in spinpolarization due to the diffusion of the excess oxygen is effective forthe enhancement of the MR ratio. In other words, if the functional layeris formed in the pinned layer 14, the free layer 18 and the cap layer 19in the TMR element, the MR may be enhanced.

The TMR film containing the functional layer can be exemplified asfollows: Ta 5 nm/Ru 2 nm/Ir₂₂Mn₇₈ 7 nm/Co₈₀Fe₂₀ 2 nm/Ru 0.9nm/(Co₈₀Fe₂₀)₈₀B₂₀ 2.4 nm/MgO 1.5 nm/Co₈₀Fe₂₀ 1 nm/Si 0.25 nm/Ni₈₅Fe₁₅3.5 nm/Cu 1 nm/Ta 2 nm/Ru 1 nm. In this film structure, the Sifunctional layer with a thickness of 0.25 nm is formed in the free layerof the TMR film.

The TMR film containing the functional layer can be exemplified asfollows: Ta 5 nm/Ru 2 nm/Ir₂₂Mn₇₈ 7 nm/Co₈₀Fe₂₀ 2 nm/Ru 0.9nm/(Co₈₀Fe₂₀)₈₀B₂₀ 0.8 nm/Si 0.125 nm/(Co₈₀Fe₂₀)₈₀B₂₀ 1.6 nm/MgO 1.5nm/Co₈₀Fe₂₀ 1 nm/Ni₈₅Fe₁₅ 3.5 nm/Cu 1 nm/Ta 2 nm/Ru 1 nm. In this filmstructure, the Si functional layer with a thickness of 0.125 nm isformed in the pinned layer of the TMR film.

The TMR film containing the functional layer can be exemplified asfollows: Ta 5 nm/Ru 2 nm/Ir₂₂Mn₇₈ 7 nm/Co₈₀Fe₂₀ 2 nm/Ru 0.9nm/(Co₈₀Fe₂₀)₈₀B₂₀ 2.4 nm/MgO 1.5 nm/Co₈₀Fe₂₀ 1 nm/Ni₈₅Fe₁₅ 3.5 nm/Si0.5 nm/Cu 0.5 nm/Ta 2 nm/Ru 1 nm. In this film structure, the Sifunctional layer with a thickness of 0.5 nm is formed in the cap layerof the TMR film.

In these embodiments, the insulating spacer layer is made of MgO. If theinsulating spacer layer is made of a material containing oxygen, the MRratio may be increased by the formation of the functional layer. As theconcrete material of the insulating layer, MgO, Al₂O₃ and TiO₂ may beemployed.

(Apparatus to be Employed for Manufacturing a Magneto-Resistance EffectElement)

FIG. 4 is a schematic view illustrating a film forming apparatus formanufacturing a magneto-resistance effect element in this embodiment.

As shown in FIG. 4, the transfer chamber (TC) 50 is disposed at thecenter of the apparatus such that the load lock chamber 51, thepre-cleaning chamber 52, the first metallic film-forming chamber (MC1)53, the second metallic film-forming chamber (MC2) 54 and the oxidelayer-nitride layer forming chamber (OC) 60 are disposed so as to beconnected with the transfer chamber 50 via the gate valves,respectively. In the apparatus, the substrate on which various films areto be formed is transferred from one chamber from another chamber underthe vacuum condition via the corresponding gate valve. Therefore, thesurface of the substrate can be maintained clean.

The metallic film-forming chambers 53 and 54 include a plurality oftargets (five to ten targets) which is called as a multi-structuredtarget. As the film forming means, a sputtering method such as a DCmagnetron sputtering or an RF magnetron sputtering, an ion beamsputtering, a vacuum deposition, a CVD (Chemical Vapor Deposition) or anMBE (Molecular Beam Epitaxy) can be employed.

(Schematic Explanation of the Method for Manufacturing aMagneto-Resistance Effect Element)

Hereinafter, the method for manufacturing a magneto-resistance effectelement will be schematically described. FIG. 5 is a flowchart of themanufacturing method of the magneto-resistance effect element in thisembodiment. First of all, on the substrate (not shown) are subsequentlyformed the bottom electrode 11, the underlayer 12, the pinning layer 13,the pinned layer 14, the bottom metallic layer 15, the spacer layer 16,the top metallic layer 17, the free layer 18, the cap layer 19 and thetop electrode 20. A substrate is set into the load lock chamber 51 sothat some metallic films are formed in the metallic film-formingchambers 53 and 54 and some oxide and/or nitride layers are formed inthe oxide layer-nitride layer forming chamber 60. The ultimate vacuum ofthe metallic film-forming chambers 53 and 54 is preferably set to 1×10⁻⁸Torr or below, normally within a range of 5×10⁻¹⁰ Torr-5×10⁻⁹ Torr. Theultimate vacuum of the transfer chamber 50 is set in the order of 10⁻⁹Torr. The ultimate vacuum of the oxide layer-nitride layer formingchamber 60 is set to 8×10⁻⁸ Torr or below. Then, the formation of eachlayer will be described.

(1) Formation of Underlayer 12 (Step S11)

The bottom electrode 11 is formed on the (not shown) substrate by meansof micro-process in advance. Then, the underlayer 12 is formed as alayer of Ta 5 nm/Ru 2 nm on the bottom electrode 11. The Ta layerfunctions as the buffer layer 12 a for relaxing the surface roughness ofthe bottom electrode 11. The Ru layer functions as the seed layer 12 bfor controlling the crystalline orientation and the crystal grain of thespin valve film to be formed thereon.

(2) Formation of Pinning Layer 13 (Step S12)

Then, the pinning layer 13 is formed on the underlayer 12. The pinninglayer 13 may be made of an antiferromagnetic material such as PtMn,PdPtMn, IrMn, RuRhMn.

(3) Formation of Pinned Layer 14 (and Functional Layer 21) (Step S13)

Then, the pinned layer 14 is formed on the pinning layer 13. The pinnedlayer 14 may be formed as the synthetic pinned layer of the bottompinned layer 141 (Co₉₀Fe₁₀)/the magnetic coupling layer 142 (Ru)/the toppinned layer 143 (Co₉₀Fe₁₀). In this case, by changing the material tobe film-formed during the formation of the top pinned layer 143, thefunctional layer 21 can be formed. Concretely, if the material isswitched to Si from Co₉₀Fe₁₀ and then, to Co₉₀Fe₁₀ from Si, the Sifunctional layer can be formed in the top pinned layer 143. If thematerial is switched to Si from Co₉₀Fe₁₀ and then, not to Co₉₀Fe₁₀ fromSi, the Si functional layer can be formed on the top pinned layer 143.

(4) Formation of Spacer Layer 15 to 17 (Step S14)

Then, the spacer layer 15 to 17 containing the current confining layer16 with the current-confined-path structure (CCP structure) is formed inthe oxide layer-nitride layer forming chamber 60.

The current confining layer 16 can be formed below. In this embodiment,the current confining layer is configured such that the currentconfining path 162 made of crystalline Cu is formed in the insulatinglayer 161 made of amorphous Al₂O₃.

1) First of all, the bottom metallic layer 15 (e.g., made of Cu) as asupplier for the current confining path is formed on the top pinnedlayer 143 (or the functional layer), and the metallic layer (e.g., AlCuor Cu) to be converted into the corresponding insulating layer is formedon the bottom metallic layer 15. Then, the pre-treatment is performedonto the metallic layer under the irradiation of ion beams of inert gassuch as Ar. The irradiation of ion beams corresponds to a pre-treatmentfor the formation of the insulating layer 161 and the current confiningpath 162, and is called as a “PIT (Pre-ion treatment)”. According to thePIT, the elements of the bottom metallic layer are pumped up andinfiltrated into the metallic layer. Therefore, the PIT is effective asan energy treatment.

2) Then, the metallic layer is oxidized by supplying oxidizing gas suchas oxygen. According to the oxidizing treatment, the metallic layer isconverted into the insulating layer 161 and the current confining path162 is formed through the insulating layer 161, thereby completing thecurrent confining layer 16. The oxidizing treatment can be performed bysupplying the oxidizing gas (oxygen gas) under the irradiation of theion beams. The treatment is called as an “IAO (Ion Assisted Oxidation)”.According to the oxidizing treatment, the current confining layer 16 canbe formed under the condition that the current confining path 162 of Cuis separated from the insulating layer 161 of Al₂O₃. The currentconfining layer 16 is formed by the difference in oxide formation energybetween the elemental Al and the elemental Cu. Then, the top metalliclayer 17 is formed of Cu on the current confining layer 16.

(5) Formation of Free Layer 18 (and Functional Layer) (Step S15)

The free layer 18 is formed on the top metallic layer 17. The free layer18 may be structured as Co₉₀Fe₁₀ 1 nm/Ni₈₃Fe₁₇ 3.5 nm. In this case, bychanging the material to be film-formed during the formation of the freelayer 18, the functional layer 21 can be formed. Concretely, if thematerial is switched to Si from Co₉₀Fe₁₀ and then, to Co₉₀Fe₁₀ from Si,the Si functional layer can be formed in the top pinned layer 143. Ifthe material is switched to Si from Co₉₀Fe₁₀ and then, not to Co₉₀Fe₁₀from Si, the

(6) Formation of Cap Layer 19 (and Functional Layer) and Top

The cap layer 19 is formed as a multilayer of Cu 1 nm/Ru 10 nm on thefree layer 18. In this case, by changing the material to be film-formedduring the formation of the cap layer 19, the functional layer can beformed. Concretely, if the material is switched to Si from Cu and then,to Cu from Si, the Si functional layer 21 can be formed in the cap layer19.

Then, the top electrode 20 is formed on the cap layer 19 so as to flow acurrent to the spin valve film in the direction perpendicular to thefilm surface thereof.

EXAMPLES

The present invention will be described in detail in view of Examples.

Example 1

In this embodiment, the film structure was configured below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 Co₇₅Fe₂₅ 3.3 nm/Ru 0.9 nm/ Fe₅₀Co₅₀ 1nm/Cu 0.25 nm × 2/Fe₅₀Co₅₀ 1 nm Metallic layer 15 Cu 0.6 nm Currentconfining layer 16 insulating layer 161 of Al₂O₃ and current confiningpath 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18 described laterCap layer 19 Cu 1 nm/Ta 2 nm/Ru 15 nm Top electrode 20

In this embodiment, the characteristics of the magneto-resistance effectelement was investigated with and without the functional layer in thefree layer 18. Example 1 corresponds to the magneto-resistance effectelement with the functional layer and Comparative Example 1 correspondsto the magneto-resistance effect element without the functional layer.The results are listed in Table 2.

TABLE 2 MR variation Free layer 18 ratio [%] Example 1 Co₆₀Fe₄₀ [2nm]/functional layer 10.5 Si [0.25 nm]/Ni₈₃Fe₁₇ [3.5 nm] ComparativeCo₆₀Fe₄₀ [2 nm]/Ni₈₃Fe₁₇ [3.5 nm] 9 Example 1

The MR ratio of the magneto-resistance effect element in Example 1 isincreased than the MR ratio of the magneto-resistance effect element inComparative Example 1 by 1.5%. It is considered that the MR enhancementis originated from the capturing effect of the excess oxygen from thespacer layer (Al₂O₃) by the Si functional layer. According to the threedimensional atom probe, it is confirmed that the Si functional layer isformed in layered-shape in the free layer 18.

Example 2

In this embodiment, the functional layer was formed at various positionsof the free layer 18 and the cap layer 19. The fundamental filmstructure will be listed below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 Co₇₅Fe₂₅ 3.9 nm/Ru 0.9 nm/ Fe₅₀Co₅₀ 1.8nm/Cu 0.25 nm/Fe₅₀Co₅₀ 1.8 nm Metallic layer 15 Cu 0.6 nm Currentconfining layer 16 insulating layer 161 of Al₂O₃ and current confiningpath 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18 described laterCap layer 19 described later Top electrode 20

The thickness of the pinned layer 14 of the film structure in Example 2is larger than the thickness of the pinned layer 14 of the filmstructure in Example 1. If the thickness of the pinned layer 14 is setlarger, the crystallinity of the top pinned layer 143 is enhanced so asto enhance the MR through the enhancement of the spin dependent bulkscattering effect. The film structure of the free layer 18 and the caplayer 19 will be listed in Table

3. In this case, the magneto-resistance effect element was manufacturedin the same manner as in Example 1. The results are listed in Table 3.

TABLE 3 MR variation Free layer 18 Cap layer 19 ratio [%] Example 2ACo₆₀Fe₄₀ [2 nm]/ Cu [1 nm]/Ta [2 nm]/Ru 12.3 functional layer [15 nm] Si[0.25 nm]/ Ni₈₃Fe₁₇ [3.5 nm] Example 2B Co₆₀Fe₄₀ [2 nm]/ Cu [1 nm]/Ta [2nm]/Ru 12.1 Ni₈₃Fe₁₇ [1.5 nm]/ [15 nm] functional layer Si [0.25 nm]/Ni₈₃Fe₁₇ [3.5 nm] Example 2C Co₆₀Fe₄₀ [2 nm]/ functional layer 12.0functional layer Si [0.25 nm]/ Si [0.25 nm]/ Cu [1 nm]/Ta [2 nm]/Ni₈₃Fe₁₇ [3.5 nm] Ru [15 nm] Comparative Co₆₀Fe₄₀ [2 nm]/ Cu [1 nm]/Ta[2 nm]/Ru 10.8 Example 2 Ni₈₃Fe₁₇ [3.5 nm] [15 nm]

The MR ratios of the magneto-resistance effect films in Example 2A,Example 2B and Example 2C are enhanced by 1.5%, 1.3% and 1.2%,respectively, in comparison with Comparative Example 2. It is consideredthat the MR enhancement is originated from the capturing effect of theexcess oxygen from the spacer layer (Al₂O₃) by the Si functional layer.According to the three dimensional atom probe, it is confirmed that theSi functional layer is formed in layered-shape in the free layer 18. Thereason the MR in Comparative Example 2 is increased than the MR inComparative Example 1 is originated from that the thickness of thepinned layer 14 in Comparative Example 2 is larger than the thickness ofthe pinned layer 14 in Comparative Example 1. As a result, it wasconfirmed that the MR can be enhanced by the formation of the functionallayer in the free layer 18 and the cap layer 19. The MR enhancementdegree in Examples 2B and 2C is smaller than the MR enhancement degreein Example 2A, which may result from that the capturing effect of theexcess oxygen in Examples 2B and 2C is lower than the capturing effectof the excess oxygen in Examples 2A because in Examples 2B and 2C, thefunctional layer is formed remote from the spacer layer. According tothe three dimensional atom probe, it is confirmed that the Si functionallayer is formed in layered-shape in the free layer 18.

Example 3

In this embodiment, the functional layers were formed in the pinnedlayer 14 and the free layer 18. The fundamental film structure will belisted below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 described later Metallic layer 15 Cu 0.6nm Current confining layer 16 insulating layer 161 of Al₂O₃ and currentconfining path 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18described later Cap layer 19 Cu 1 nm/Ta 2 nm/Ru 15 nm Top electrode 20

The film structure of the pinned layer 14 and the free layer 18 will belisted in Table 4. In Example 3, the Si functional layer is formed inthe top pinned layer 143, which is different from Example 2. The resultsare listed in Table 4.

TABLE 4 MR variation Pinned layer 14 Free layer 14 ratio [%] Example 3Co₇₅Fe₂₅ [3.9 nm]/Ru Co₆₀Fe₄₀ [2 nm]/ 12.8 [0.9 nm]/Fe₅₀Co₅₀ [0.6 nm]/functional layer functional layer Si [0.25 nm]/ Si [0.25 nm]/ Fe₅₀Co₅₀[1.2 nm]/Cu Ni₈₃Fe₁₇ [3.5 nm] [0.25 nm]/Fe₅₀Co₅₀ [1.8 nm] ExampleCo₇₅Fe₂₅ [3.9 nm]/Ru Co₆₀Fe₄₀ [2 nm]/ 12.3 2A [0.9 nm]/Fe₅₀Co₅₀ [1.8nm]/ functional layer Cu [0.25 nm]/ Si [0.25 nm]/ Fe₅₀Co₅₀ [1.8 nm]Ni₈₃Fe₁₇ [3.5 nm] Compara- Co₇₅Fe₂₅ [3.9 nm]/Ru Co₆₀Fe₄₀ [2 nm]/ 10.8tive [0.9 nm]/Fe₅₀Co₅₀ [1.8 nm]/ Ni₈₃Fe₁₇ [3.5 nm] Example 2 Cu [0.25nm]/ Fe₅₀Co₅₀ [1.8 nm]

The MR ratio of the magneto-resistance effect film in Example 3 isenhanced by 2.0%, in comparison with Comparative Example 2, and isenhanced by 0.5%, in comparison with Example 2A. It is confirmed thatthe MR ratio of the CCP-GMR film can be enhanced by the formation of theSi functional layer into pinned layer 14. According to the threedimensional atom probe, it is confirmed that the Si functional layer isformed in layered-shape in the free layer 18.

Example 4

In this embodiment, the thickness of the functional layer was varied.The fundamental film structure will be listed below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 Co₇₅Fe₂₅ 3.9 nm/Ru 0.9 nm/ Fe₅₀Co₅₀ 1.8nm/Cu 0.25 nm/Fe₅₀Co₅₀ 1.8 nm Metallic layer 15 Cu 0.6 nm Currentconfining layer 16 insulating layer 161 of Al₂O₃ and current confiningpath 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18 described laterCap layer 19 Cu 1 nm/Ta 2 nm/Ru 15 nm Top electrode 20

The results are listed in Table 5.

TABLE 5 MR variation Free layer 18 ratio [%] Example 4 Co₆₀Fe₄₀ [2nm]/functional layer 12.3 Si [0.5 nm]/Ni₈₃Fe₁₇ [3.5 nm] Example 2ACo₆₀Fe₄₀ [2 nm]/functional layer 12.3 Si [0.25 nm]/Ni₈₃Fe₁₇ [3.5 nm]Comparative Co₆₀Fe₄₀ [2 nm]/Ni₈₃Fe₁₇ [3.5 nm] 10.8 Example 2

The MR ratio of the magneto-resistance effect film in Example 4 isenhanced by 1.50, in comparison with Comparative Example 2, whichcorresponds to the enhancement degree of the MR ratio in the case ofExample 1 and Comparative Example 1. Herein, the thickness of the Sifunctional layer in Example 4 is set larger than the thickness of the Sifunctional layer in Example 1. It is considered that the MR enhancementis originated from the capturing effect of the excess oxygen from thespacer layer (Al₂O₃) by the Si functional layer. According to the threedimensional atom probe, it is confirmed that the Si functional layer isformed in layered-shape in the free layer 18.

Example 5

In this embodiment, the functional layer was formed in the free layers18, each free layer having the respective different film structure fromanother one. The fundamental film structure will be listed below.

Bottom electrode 11 Underlayer 12 Ta 5 nm/Ru 2 nm Pinning layer 13Ir₂₂Mn₇₈ 7 nm Pinned layer 14 Co₇₅Fe₂₅ 3.9 nm/Ru 0.9 nm/ Fe₅₀Co₅₀ 1.8nm/Cu 0.25 nm/Fe₅₀Co₅₀ 1.8 nm Metallic layer 15 Cu 0.6 nm Currentconfining layer 16 insulating layer 161 of Al₂O₃ and current confiningpath 162 of Cu Metallic layer 17 Cu 0.4 nm Free layer 18 described laterCap layer 19 Cu 1 nm/Ta 2 nm/Ru 15 nm Top electrode 20

The film structure of each free layer 18 is listed in Table 6. InComparative Examples 3, 2, 4, the composition of the FeCo alloy of thefree layer 18 is varied at the interface between the free layer 18 andthe spacer layer. The Fe composition is set to 10 at %, 40 at % and 50at % in Comparative Examples 3, 2, 4, respectively. In Examples 5A, 2A,5B, the Si functional layer is formed in the corresponding fundamentalfilm structures in Comparative Examples 3, 2, 4, respectively. Theresults are listed in Table 6. In this case, the MR enhancement can bedetermined dependent on the film structure of the free layer in whichthe functional layer is formed.

TABLE 6 MR variation Free layer 18 ratio [%] Example 5A Co₅₀Fe₅₀ [2nm]/functional layer Si [0.25 nm]/ 12.8 Ni₈₃Fe₁₇ [3.5 nm] Example 2ACo₆₀Fe₄₀ [2 nm]/functional layer Si [0.25 nm]/ 12.3 Ni₈₃Fe₁₇ [3.5 nm]Example 5B Co₉₀Fe₁₀ [2 nm]/functional layer Si [0.25 nm]/ 10.3 Ni₈₃Fe₁₇[3.5 nm] Comparative Co₅₀Fe₅₀ [2 nm]/Ni₈₃Fe₁₇ [3.5 nm] 10.8 Example 3Comparative Co₆₀Fe₄₀ [2 nm]/Ni₈₃Fe₁₇ [3.5 nm] 10.8 Example 2 ComparativeCo₉₀Fe₁₀ [2 nm]/Ni₈₃Fe₁₇ [3.5 nm] 9.8 Example 4

The MR ratio of the magneto-resistance effect film in Example 5A isenhanced by 2.2%, in comparison with Comparative Example 3. It isconsidered that the MR enhancement is originated from the capturingeffect of the excess oxygen from the spacer layer (Al₂O₃) by the Sifunctional layer. In view of the composition of the FeCo alloy of thefree layer 14 in addition to the formation of the Si functional layerfor the MR enhancement, the MR ratio is increased by 0.5% at the Fecomposition of 10 at. % at the interface between the free layer 18 andthe spacer, and by 1.5% at the Fe composition of 40 at. % thereat, andby 2.2% at the Fe composition of 50 at. % thereat. It is apparent,therefore, that the MR ratio due to the functional layer is increased asthe Fe composition is increased.

The reason the MR ratio is increased as the Fe composition is increasedcan be considered as follows. The oxide formation energy of Fe is lowerthan Co referring to Table 1 so that the elemental Fe is likely to beoxidized than Co. As a result, when the free layer 18 is made of amaterial with Fe-rich composition, the free layer 18 are likely to beoxidized from the excess oxygen of the spacer layer. Therefore, the MRratio can be easily increased by the capturing effect of excess oxygendue to the formation of the Si functional layer. According to the threedimensional atom probe, it is confirmed that the Si functional

(Application of Magneto-Resistance Effect Element)

The application of the magneto-resistance effect element according tothis embodiment will be described hereinafter,

In view of high density recording, the element resistance RA is setpreferably to 500 mΩμm² or below, more preferably to 300 mΩμm² or below.In the calculation of the element resistance RA, the effective area A incurrent flow of the spin valve film is multiplied to the resistance R ofthe CPP-CPP element. Herein, the element resistance R can be directlymeasured, but attention should be paid to the effective area A becausethe effective area A depends on the element structure.

If the whole area of the spin valve film is effectively sensed bycurrent through patterning, the whole area of the spin valve filmcorresponds to the effective area A. In this case, the whole area of thespin valve film is set to 0.04 μm² or below in view of the appropriateelement resistance, and to 0.02 μm² or below in view of the recordingdensity of 200 Gbpsi or over.

If the area of the bottom electrode 11 or the top electrode 20 is setsmaller than the whole area of the spin valve film, the area of thebottom electrode 11 or the top electrode 20 corresponds to the effectivearea A. If the area of the bottom electrode 11 is different from thearea of the top electrode 20, the smaller area of either of the bottomelectrode 11 or the top electrode 20 corresponds to the effective areaA. As described above, the smaller area is set to 0.04 μm² or below inview of the appropriate element resistance.

Referring to FIGS. 6 and 7, since the smallest area of the spin valvefilm 10 corresponds to the contacting area with the top electrode 20 asapparent from FIG. 6, the width of the smallest area can be consideredas a track width Tw. Then, since the smallest area of the spin valvefilm. 10 in MR height direction also corresponds to the contacting areawith the top electrode 20 as apparent from FIG. 7, the width of thesmallest are can be considered as a height length D. In this case, theeffective area A can be calculated on the equation of A=Tw×D.

In the magneto-resistance effect element according to this embodiment,the resistance R between the electrodes can be reduced to 100Ω or below,which corresponds to the resistance between the electrode pads in thereproducing head attached to the forefront of a head gimbal assembly(HGA), for example.

It is desired that the magneto-resistance effect element is structuredin fcc (111) orientation when the pinned layer 14 or the free layer 18has the fcc-structure. It is also desired that the magneto-resistanceeffect element is structured in bcc (100) orientation when the pinnedlayer 14 or the free layer 18 has the bcc-structure. It is also desiredthat the magneto-resistance effect element is structured in hcp (001)orientation when the pinned layer 14 or the free layer 18 has thehcp-structure.

The crystalline orientation of the magneto-resistance effect elementaccording to this embodiment is preferably 4.5 degrees or below, morepreferably 3.5 degrees or below and particularly 3.0 degree or below inview of the dispersion of orientation. The crystalline orientation canbe measured from the FWHM of X-ray rocking curve obtained from the 8-28measurement in X-ray diffraction. The crystalline orientation can bealso measured by the spot scattering angle originated from thenano-diffraction spots of the element cross section.

Depending on the kind of material of the antiferromagnetic film, sincethe lattice spacing of the antiferromagnetic film is different from thelattice spacing of the pinned layer 14/current confining layer 16/freelayer 18, the dispersion in crystalline orientation can be obtainedbetween the antiferromagnetic film and the pinned layer 14/currentconfining layer 16/free layer 18. For example, the lattice spacing ofthe PtMn antiferromagnetic layer is often different from the latticespacing of the pinned layer 14/Current confining layer 16/free layer 18.In this point of view, since the PtMn layer is formed thicker, the PtMnlayer is suitable for the measurement in dispersion of the crystalorientation. With the pinned layer 14/current confining layer 16/freelayer 18, the pinned layer 14 and the free layer 18 may have therespective different crystal structures of bcc-structure andfcc-structure. In this case, the dispersion angle in crystal orientationof the pinned layer 14 may be different from the dispersion angle incrystal orientation of the free layer 18.

(Magnetic Head)

FIGS. 6 and 7 are cross sectional views showing the state where themagneto-resistance effect element according to this embodiment isincorporated in a magnetic head. FIG. 6 is a cross sectional viewshowing the magneto-resistance effect element, taken on the surfacealmost parallel to the ABS (air bearing surface) opposite to a (notshown) magnetic recording medium. FIG. 7 is a cross sectional viewshowing the magneto-resistance effect element, taken on the surfacealmost perpendicular to the ABS.

The magnetic head shown in FIGS. 6 and 7 has a so-called hard abuttedstructure. The magneto-resistance effect film 10 is the CCP-CPP film asdescribed above. The bottom electrode 11 and the top electrode 20 areprovided on the top surface and the bottom surface of themagneto-resistance effect film 10, respectively. In FIG. 6, the biasingmagnetic applying films 41 and the insulating films 42 are formed at theboth sides of the magneto-resistance effect film 10. In FIG. 7, theprotective layer 43 is formed on the ABS of the magneto-resistanceeffect film 10.

The sense current is flowed along the arrow A through themagneto-resistance effect film 10 between the bottom electrode 11 andthe top electrode 20, that is, in the direction perpendicular to thefilm surface of the magneto-resistance effect film 10. Moreover, a givenbiasing magnetic field is applied to the magneto-resistance effect film10 from the biasing magnetic field applying films 41 so as to render thedomain structure of the free layer 18 of the film 10 a single domainstructure through the control of the magnetic anisotropy of the freelayer 18 and stabilize the magnetic domain structure of the free layer18. In this case, the Barkhausen noise due to the shift of magnetic wallin the magneto-resistance effect film 10 can be prevented.

Since the S/N ratio of the magneto-resistance effect film 10 isenhanced, the magnetic head including the magneto-resistance effect film10 can realize the high sensitive magnetic reproduction.

(Magnetic Head and Magnetic Recording/Reproducing Device)

The magneto-resistance effect element is installed in advance in anall-in-one magnetic head assembly allowing both therecording/reproducing, and mounted as the head assembly at the magneticrecording/reproducing device.

FIG. 8 is a perspective view illustrating the schematic structure of themagnetic recording/reproducing device. The magneticrecording/reproducing device 150 illustrated in FIG. 8 constitutes arotary actuator type magnetic recording/reproducing device. In FIG. 8, amagnetic recording disk 200 is mounted to a spindle 152 to be turned inthe direction designated by the arrow A by a motor (not shown) which isdriven in response to control signals from a drive unit controller (notshown). In FIG. 8, the magnetic recording/reproducing apparatus 150 maybe that provided with a single magnetic recording disk 200, but with aplurality of magnetic recording disks 200.

A head slider 153 recording/reproducing information to be stored in themagnetic recording disk 200 is mounted on a tip of a suspension 154 of athin film type. The head slider 153 mounts at the tip the magnetic headcontaining the magnetic resistance effect element as described in aboveembodiments.

When the magnetic recording disk 200 is rotated, such a surface (ABS) ofthe head slider 153 as being opposite to the magnetic recording disk 200is floated from on the main surface of the magnetic recording disk 200.Alternatively, the slider may constitute a so-called “contact runningtype” slider such that the slider is in contact with the magneticrecording disk 200.

The suspension 154 is connected to one edge of the actuator arm 155 witha bobbin portion supporting a driving coil (not shown) and the like. Avoice coil motor 156 being a kind of a linear motor is provided at theother edge of the actuator arm 155. The voice coil motor 156 is composedof the driving coil (not shown) wound around the bobbin portion of theactuator arm 155 and a magnetic circuit with a permanent magnet and acounter yoke which are disposed opposite to one another so as tosandwich the driving coil.

The actuator arm 155 is supported by ball bearings (not shown) providedat the upper portion and the lower portion of the spindle 157 so as tobe rotated and slid freely by the voice coil motor 156.

FIG. 9 is an enlarged perspective view illustrating a portion of themagnetic head assembly positioned at the tip side thereof from theactuator arm 155, as viewed from the side of the magnetic recording disk200. As illustrated in FIG. 9, the magnetic head assembly 160 has theactuator arm 155 with the bobbin portion supporting the driving coil andthe like. The suspension 154 is connected with the one edge of theactuator arm 155. Then, the head slider 153 with the magnetic headcontaining the magneto-resistance effect element as defined inabove-embodiments is attached to the tip of the suspension 154. Thesuspension 154 includes a lead wire 164 for writing/reading signals,where the lead wire 164 is electrically connected with the respectiveelectrodes of the magnetic head embedded in the head slider 153. In thedrawing, reference numeral “165” denotes an electrode pad of theassembly 160.

In the magnetic recording/reproducing device illustrated in FIGS. 8 and9, since the magneto-resistance effect element as described in the aboveembodiments is installed, the information magnetically recorded in themagnetic recording disk 200 can be read out properly.

(Magnetic Memory)

The magneto-resistance effect element as described above can constitutea magnetic memory such as a magnetic random access memory (MRAM) wherememory cells are arranged in matrix.

FIG. 10 is a view illustrating an embodiment of the magnetic memorymatrix according to the present invention. This drawing shows a circuitconfiguration when the memory cells are arranged in an array. In orderto select one bit in the array, a column decoder 350 and a line decoder351 are provided, where a switching transistor 330 is turned ON by a bitline 334 and a word line 332 and to be selected uniquely, so that thebit information recorded in a magnetic recording layer (free layer) inthe magneto-resistance effect film 10 can be read out by being detectedby a sense amplifier 352. In order to write the bit information, awriting current is flowed in a specific write word line 323 and a bitline 322 to generate a magnetic field for writing.

FIG. 11 is a view illustrating another embodiment of the magnetic memorymatrix according to the present invention. In this case, a bit line 322and a word line 334 which are arranged in matrix are selected bydecoders 360, 361, respectively, so that a specific memory cell in thearray is selected. Each memory cell is configured such that themagneto-resistance effect film 10 and a diode D is connected in series.Here, the diode D plays a role of preventing a sense current fromdetouring in the memory cell other than the selected magneto-resistanceeffect film 10. A writing is performed by a magnetic field generated byflowing the writing current in the specific bit line 322 and the wordline 323, respectively.

FIG. 12 is a cross sectional view illustrating a substantial portion ofthe magnetic memory in an embodiment according to the present invention.FIG. 13 is a cross sectional view of the magnetic memory illustrated inFIG. 12, taken on line “A-A′”. The configuration shown in these drawingscorresponds to a 1-bit memory cell included in the magnetic memory shownin FIG. 10 or FIG. 11. This memory cell includes a memory element part311 and an address selection transistor part 312.

The memory element part 311 includes the magneto-resistance effect film10 and a pair of wirings 322, 324 connected to the magneto-resistanceeffect film 10. The magneto-resistance effect film 10 is themagneto-resistance effect element (CCP-CPP element) as described in theabove embodiments.

Meanwhile, in the address selection transistor part 312, a transistor330 having connection therewith via a via 326 and an embedded wiring 328is provided. The transistor 330 performs switching operations inaccordance with voltages applied to a gate 332 to control theopening/closing of the current confining path between themagneto-resistance effect film. 10 and the wiring 334.

Further, below the magneto-resistance effect film 10, a write wiring 323is provided in the direction substantially orthogonal to the wiring 322.These write wirings 322, 323 can be formed of, for example, aluminum(Al), copper (Cu), tungsten (W), tantalum (Ta) or an alloy containingany of these elements.

In the memory cell of such a configuration, when writing bit informationinto the magneto-resistance effect element 10, a writing pulse currentis flowed in the wirings 322, 323, and a synthetic magnetic fieldinduced by the writing current is applied to appropriately invert themagnetization of a recording layer of the magneto-resistance effectelement 10.

Further, when reading out the bit information, a sense current is flowedthrough the magneto-resistance effect element 10 including the magneticrecording layer and a lower electrode 324 to measure a resistance valueof or a fluctuation in the resistance values of the magneto-resistanceeffect element 10.

The magnetic memory according to the embodiment can assure writing andreading by surely controlling the magnetic domain of the recording layereven though the cell is miniaturized in size, with the use of themagneto-resistance effect element (CCP-CPP element) according to theabove-described embodiment.

Another Embodiment

Although the present invention was described in detail with reference tothe above examples, this invention is not limited to the abovedisclosure and every kind of variation and modification may be madewithout departing from the scope of the present invention.

The concrete structure of the magneto-resistance effect element, and theshape and material of the electrodes, the magnetic field biasing filmsand the insulating layer can be appropriately selected among the oneswell known by the person skilled in the art. In these cases, theintended magneto-resistance effect element according to the presentinvention can be obtained so as to exhibit the same effect/function asdescribed above.

When the magneto-resistance effect element is applied for a reproducingmagnetic head, the detecting resolution of the magnetic head can bedefined by applying magnetic shielding for the upper side and the lowerside of the magneto-resistance effect element. Moreover, themagneto-resistance effect element can be applied for both of alongitudinal magnetic recording type magnetic head and a verticalmagnetic recording type magnetic recording type magnetic head. Also, themagneto-resistance effect element can be applied for both of alongitudinal magnetic recording/reproducing device and a verticalmagnetic recording/reproducing device. The magneticrecording/reproducing device may be a so-called stationary type magneticdevice where a specific recording medium is installed therein or aso-called removable type magnetic device where a recording medium can bereplaced.

What is claimed is:
 1. A magneto-resistance effect element, comprising:a bottom electrode; a first fixed magnetization layer formed on or abovethe bottom electrode, the first fixed magnetization layer having amagnetization substantially fixed in one direction; a magnetic couplinglayer formed on the first fixed magnetization layer; a second fixedmagnetization layer formed on the magnetic coupling layer, the secondfixed magnetization layer having a magnetization substantially fixed inone direction; a free magnetization layer formed opposite to the firstfixed magnetization layer, the free magnetization layer having amagnetization rotated in accordance with an external magnetic field; aspacer layer disposed between the second fixed magnetization layer andthe free magnetization layer, the spacer layer including a currentconfining layer, the current confining layer having an insulating layerand a conductor to pass a current through the insulating layer in athickness direction thereof, the insulating layer including oxide,nitride or oxynitride; a functional layer formed in or on the secondfixed magnetization layer, the functional layer containing at least oneelement selected from the group consisting of Si, Mg, B, and Al; and atop electrode formed on or above the free magnetization layer, the topelectrode being configured to pass electric current in combination withthe bottom electrode.
 2. The magneto-resistance effect element as setforth in claim 1, wherein the functional layer contains Si.
 3. Themagneto-resistance effect element as set forth in claim 1, wherein athickness of the functional layer is within 0.1 to 10 nm.
 4. Themagneto-resistance effect element as set forth in claim 1, wherein thespacer layer includes a metallic layer formed so as to be adjacent tothe current confining layer and at least one of the second fixedmagnetization layer and the free magnetization layer.
 5. Themagneto-resistance effect element as set forth in claim 4, wherein themetallic layer includes at least one element selected from the groupconsisting of Cu, Ag, and Au.
 6. The magneto-resistance effect elementas set forth in claim 1, wherein the conductor of the current confininglayer mainly contains at least one element selected from the groupconsisting of Cu, Ag, and Au.
 7. The magneto-resistance effect elementas set forth in claim 1, wherein at least one of the second fixedmagnetization layer and/or the free magnetization layer contains Fe. 8.The magneto-resistance effect element as set forth in claim 7, whereinan Fe composition in a region of the second fixed magnetization layerand/or the free magnetization layer remote from the spacer layer by 1 nmor less is set to 10% or more.
 9. The magneto-resistance effect elementas set forth in claim 7, wherein an Fe composition in a region of thesecond fixed magnetization layer and/or the free magnetization layerremote from the spacer layer by 1 nm or less is set to 40% or more. 10.A magneto-resistance effect element, comprising: a bottom electrode; afirst fixed magnetization layer formed on or above the bottom electrode,the first fixed magnetization layer having a magnetization substantiallyfixed in one direction; a magnetic coupling layer formed on the firstfixed magnetization layer; a second fixed magnetization layer formed onthe magnetic coupling layer, the second fixed magnetization layer havinga magnetization substantially fixed in one direction; a spacer layerincluding a first metallic layer, a current confining layer, and asecond metallic layer subsequently stacked therein on the second fixedmagnetization layer, the first metallic layer containing at least oneelement selected from the group consisting of Cu, Ag, and Au, thecurrent confining layer having an insulating layer and a conductor topass a current through the insulating layer in a thickness directionthereof, the insulating layer including oxide, nitride or oxynitride,the conductor containing at least one element selected from the groupconsisting of Cu, Al, and Au, the second metallic layer containing atleast one element selected from the group consisting of Cu, Ag, and Au;a free magnetization layer formed on the spacer layer, the freemagnetization layer having a magnetization rotated in accordance with anexternal magnetic field; a functional layer formed in or on the secondfixed magnetization layer, the functional layer containing at least oneelement selected from the group consisting of Si, Mg, B, and Al; and atop electrode formed on or above the free magnetization layer, the topelectrode being configured to pass electric current in combination withthe bottom electrode, wherein an Fe composition in a region of thesecond fixed magnetization layer and/or the free magnetization layerremote from the spacer layer by 1 nm or less is set to 10% or more. 11.The magneto-resistance effect element as set forth in claim 10, whereinthe Fe composition in the region of the second fixed magnetization layerand/or the free magnetization layer remote from the spacer layer by 1 nmor less is set to 40% or more.
 12. A magneto-resistance effect element,comprising: a bottom electrode; a first fixed magnetization layer formedon or above the bottom electrode, the first fixed magnetization having amagnetization substantially fixed in one direction; a magnetic couplinglayer formed on the first fixed magnetization layer; a second fixedmagnetization layer formed on the magnetic coupling layer, the secondfixed magnetization layer having a magnetization substantially fixed inone direction; a free magnetization layer formed opposite to the secondfixed magnetization layer, the free magnetization layer having amagnetization rotated in accordance with an external magnetic field; aninsulating spacer layer disposed between the second fixed magnetizationlayer and the free magnetization layer, the insulating spacer layerpassing a tunnel current therethrough; a functional layer formed in oron the second fixed magnetization layer, the functional layer containingat least one element selected from the group consisting of Si, Mg, B,and Al; and a top electrode formed on or above the free magnetizationlayer, the top electrode being configured to pass electric current incombination with the bottom electrode.
 13. The magneto-resistance effectelement as set forth in claim 12, wherein a thickness of the functionallayer is within 0.1 to 10 nm.
 14. The magneto-resistance effect elementas set forth in claim 13, wherein at least one of the second fixedmagnetization layer and/or the free magnetization layer contains Fe. 15.The magneto-resistance effect element as set forth in claim 14, whereinan Fe composition in a region of the second fixed magnetization layerand/or the free magnetization layer remote from the spacer layer by 1 nmor less is set to 10% or more.
 16. The magneto-resistance effect elementas set forth in claim 14, wherein an Fe composition in a region of thesecond fixed magnetization layer and/or the free magnetization layerremote from the spacer layer by 1 nm or less is set to 40% or more. 17.A magnetic head, comprising a magneto-resistance effect element as setforth in claim
 1. 18. A magnetic recording/reproducing device,comprising a magnetic head as set forth in claim 15 and a magneticrecording medium.
 19. A magnetic memory, comprising a magneto-resistanceeffect element as set forth claim 1.